diff --git a/atom/browser/api/atom_api_window.cc b/atom/browser/api/atom_api_window.cc
index 0d72a74f7d..cc3749bd01 100644
--- a/atom/browser/api/atom_api_window.cc
+++ b/atom/browser/api/atom_api_window.cc
@@ -95,9 +95,16 @@ Window::Window(v8::Isolate* isolate, const mate::Dictionary& options) {
   mate::Dictionary(isolate, web_contents->GetWrapper()).Set(
       "browserWindowOptions", options);
 
+  // The parent window.
+  mate::Handle<Window> parent;
+  if (options.Get("parent", &parent))
+    parent_window_.Reset(isolate, parent.ToV8());
+
   // Creates BrowserWindow.
-  window_.reset(NativeWindow::Create(web_contents->managed_web_contents(),
-                                     options));
+  window_.reset(NativeWindow::Create(
+      web_contents->managed_web_contents(),
+      options,
+      parent.IsEmpty() ? nullptr : parent->window_.get()));
   web_contents->SetOwnerWindow(window_.get());
   window_->InitFromOptions(options);
   window_->AddObserver(this);
@@ -120,10 +127,32 @@ Window::~Window() {
   base::MessageLoop::current()->DeleteSoon(FROM_HERE, window_.release());
 }
 
+void Window::AfterInit(v8::Isolate* isolate) {
+  mate::TrackableObject<Window>::AfterInit(isolate);
+
+  // We can only append this window to parent window's child windows after this
+  // window's JS wrapper gets initialized.
+  mate::Handle<Window> parent;
+  if (!parent_window_.IsEmpty() &&
+      mate::ConvertFromV8(isolate, GetParentWindow(), &parent))
+    parent->child_windows_.Set(isolate, ID(), GetWrapper());
+}
+
 void Window::WillCloseWindow(bool* prevent_default) {
   *prevent_default = Emit("close");
 }
 
+void Window::WillDestoryNativeObject() {
+  // Close all child windows before closing current window.
+  v8::Locker locker(isolate());
+  v8::HandleScope handle_scope(isolate());
+  for (v8::Local<v8::Value> value : child_windows_.Values(isolate())) {
+    mate::Handle<Window> child;
+    if (mate::ConvertFromV8(isolate(), value, &child))
+      child->window_->CloseImmediately();
+  }
+}
+
 void Window::OnWindowClosed() {
   api_web_contents_->DestroyWebContents();
 
@@ -136,6 +165,8 @@ void Window::OnWindowClosed() {
 
   Emit("closed");
 
+  RemoveFromParentChildWindows();
+
   // Destroy the native class when window is closed.
   base::MessageLoop::current()->PostTask(FROM_HERE, GetDestroyClosure());
 }
@@ -280,6 +311,10 @@ void Window::Show() {
 }
 
 void Window::ShowInactive() {
+  // This method doesn't make sense for modal window..
+  if (IsModal())
+    return;
+
   window_->ShowInactive();
 }
 
@@ -291,6 +326,10 @@ bool Window::IsVisible() {
   return window_->IsVisible();
 }
 
+bool Window::IsEnabled() {
+  return window_->IsEnabled();
+}
+
 void Window::Maximize() {
   window_->Maximize();
 }
@@ -650,6 +689,42 @@ void Window::SetAspectRatio(double aspect_ratio, mate::Arguments* args) {
   window_->SetAspectRatio(aspect_ratio, extra_size);
 }
 
+void Window::SetParentWindow(v8::Local<v8::Value> value,
+                             mate::Arguments* args) {
+  if (IsModal()) {
+    args->ThrowError("Can not be called for modal window");
+    return;
+  }
+
+  mate::Handle<Window> parent;
+  if (value->IsNull()) {
+    RemoveFromParentChildWindows();
+    parent_window_.Reset();
+    window_->SetParentWindow(nullptr);
+  } else if (mate::ConvertFromV8(isolate(), value, &parent)) {
+    parent_window_.Reset(isolate(), value);
+    window_->SetParentWindow(parent->window_.get());
+    parent->child_windows_.Set(isolate(), ID(), GetWrapper());
+  } else {
+    args->ThrowError("Must pass BrowserWindow instance or null");
+  }
+}
+
+v8::Local<v8::Value> Window::GetParentWindow() const {
+  if (parent_window_.IsEmpty())
+    return v8::Null(isolate());
+  else
+    return v8::Local<v8::Value>::New(isolate(), parent_window_);
+}
+
+std::vector<v8::Local<v8::Object>> Window::GetChildWindows() const {
+  return child_windows_.Values(isolate());
+}
+
+bool Window::IsModal() const {
+  return window_->is_modal();
+}
+
 v8::Local<v8::Value> Window::GetNativeWindowHandle() {
   gfx::AcceleratedWidget handle = window_->GetAcceleratedWidget();
   return ToBuffer(
@@ -675,6 +750,17 @@ v8::Local<v8::Value> Window::WebContents(v8::Isolate* isolate) {
     return v8::Local<v8::Value>::New(isolate, web_contents_);
 }
 
+void Window::RemoveFromParentChildWindows() {
+  if (parent_window_.IsEmpty())
+    return;
+
+  mate::Handle<Window> parent;
+  if (!mate::ConvertFromV8(isolate(), GetParentWindow(), &parent))
+    return;
+
+  parent->child_windows_.Remove(ID());
+}
+
 // static
 void Window::BuildPrototype(v8::Isolate* isolate,
                             v8::Local<v8::ObjectTemplate> prototype) {
@@ -688,6 +774,7 @@ void Window::BuildPrototype(v8::Isolate* isolate,
       .SetMethod("showInactive", &Window::ShowInactive)
       .SetMethod("hide", &Window::Hide)
       .SetMethod("isVisible", &Window::IsVisible)
+      .SetMethod("isEnabled", &Window::IsEnabled)
       .SetMethod("maximize", &Window::Maximize)
       .SetMethod("unmaximize", &Window::Unmaximize)
       .SetMethod("isMaximized", &Window::IsMaximized)
@@ -697,6 +784,12 @@ void Window::BuildPrototype(v8::Isolate* isolate,
       .SetMethod("setFullScreen", &Window::SetFullScreen)
       .SetMethod("isFullScreen", &Window::IsFullscreen)
       .SetMethod("setAspectRatio", &Window::SetAspectRatio)
+#if !defined(OS_WIN)
+      .SetMethod("setParentWindow", &Window::SetParentWindow)
+#endif
+      .SetMethod("getParentWindow", &Window::GetParentWindow)
+      .SetMethod("getChildWindows", &Window::GetChildWindows)
+      .SetMethod("isModal", &Window::IsModal)
       .SetMethod("getNativeWindowHandle", &Window::GetNativeWindowHandle)
       .SetMethod("getBounds", &Window::GetBounds)
       .SetMethod("setBounds", &Window::SetBounds)
diff --git a/atom/browser/api/atom_api_window.h b/atom/browser/api/atom_api_window.h
index 9d3f7ef240..21ecca4c72 100644
--- a/atom/browser/api/atom_api_window.h
+++ b/atom/browser/api/atom_api_window.h
@@ -6,15 +6,16 @@
 #define ATOM_BROWSER_API_ATOM_API_WINDOW_H_
 
 #include <map>
+#include <memory>
 #include <string>
 #include <vector>
 
-#include "base/memory/scoped_ptr.h"
 #include "ui/gfx/image/image.h"
 #include "atom/browser/api/trackable_object.h"
 #include "atom/browser/native_window.h"
 #include "atom/browser/native_window_observer.h"
 #include "atom/common/api/atom_api_native_image.h"
+#include "atom/common/key_weak_map.h"
 #include "native_mate/handle.h"
 
 class GURL;
@@ -54,8 +55,12 @@ class Window : public mate::TrackableObject<Window>,
   Window(v8::Isolate* isolate, const mate::Dictionary& options);
   ~Window() override;
 
+  // TrackableObject:
+  void AfterInit(v8::Isolate* isolate) override;
+
   // NativeWindowObserver:
   void WillCloseWindow(bool* prevent_default) override;
+  void WillDestoryNativeObject() override;
   void OnWindowClosed() override;
   void OnWindowBlur() override;
   void OnWindowFocus() override;
@@ -94,6 +99,7 @@ class Window : public mate::TrackableObject<Window>,
   void ShowInactive();
   void Hide();
   bool IsVisible();
+  bool IsEnabled();
   void Maximize();
   void Unmaximize();
   bool IsMaximized();
@@ -159,6 +165,10 @@ class Window : public mate::TrackableObject<Window>,
   void SetMenuBarVisibility(bool visible);
   bool IsMenuBarVisible();
   void SetAspectRatio(double aspect_ratio, mate::Arguments* args);
+  void SetParentWindow(v8::Local<v8::Value> value, mate::Arguments* args);
+  v8::Local<v8::Value> GetParentWindow() const;
+  std::vector<v8::Local<v8::Object>> GetChildWindows() const;
+  bool IsModal() const;
   v8::Local<v8::Value> GetNativeWindowHandle();
 
 #if defined(OS_WIN)
@@ -181,6 +191,9 @@ class Window : public mate::TrackableObject<Window>,
   int32_t ID() const;
   v8::Local<v8::Value> WebContents(v8::Isolate* isolate);
 
+  // Remove this window from parent window's |child_windows_|.
+  void RemoveFromParentChildWindows();
+
 #if defined(OS_WIN)
   typedef std::map<UINT, MessageCallback> MessageCallbackMap;
   MessageCallbackMap messages_callback_map_;
@@ -188,6 +201,8 @@ class Window : public mate::TrackableObject<Window>,
 
   v8::Global<v8::Value> web_contents_;
   v8::Global<v8::Value> menu_;
+  v8::Global<v8::Value> parent_window_;
+  KeyWeakMap<int> child_windows_;
 
   api::WebContents* api_web_contents_;
 
diff --git a/atom/browser/native_window.cc b/atom/browser/native_window.cc
index 844bbefa9e..4eb72dfe08 100644
--- a/atom/browser/native_window.cc
+++ b/atom/browser/native_window.cc
@@ -46,7 +46,8 @@ namespace atom {
 
 NativeWindow::NativeWindow(
     brightray::InspectableWebContents* inspectable_web_contents,
-    const mate::Dictionary& options)
+    const mate::Dictionary& options,
+    NativeWindow* parent)
     : content::WebContentsObserver(inspectable_web_contents->GetWebContents()),
       has_frame_(true),
       transparent_(false),
@@ -56,12 +57,17 @@ NativeWindow::NativeWindow(
       sheet_offset_x_(0.0),
       sheet_offset_y_(0.0),
       aspect_ratio_(0.0),
+      parent_(parent),
+      is_modal_(false),
       inspectable_web_contents_(inspectable_web_contents),
       weak_factory_(this) {
   options.Get(options::kFrame, &has_frame_);
   options.Get(options::kTransparent, &transparent_);
   options.Get(options::kEnableLargerThanScreen, &enable_larger_than_screen_);
 
+  if (parent)
+    options.Get("modal", &is_modal_);
+
   // Tell the content module to initialize renderer widget with transparent
   // mode.
   ui::GpuSwitchingManager::SetTransparent(transparent_);
@@ -292,6 +298,10 @@ bool NativeWindow::HasModalDialog() {
   return has_dialog_attached_;
 }
 
+void NativeWindow::SetParentWindow(NativeWindow* parent) {
+  parent_ = parent;
+}
+
 void NativeWindow::FocusOnWebView() {
   web_contents()->GetRenderViewHost()->GetWidget()->Focus();
 }
@@ -397,6 +407,9 @@ void NativeWindow::CloseContents(content::WebContents* source) {
   inspectable_web_contents_ = nullptr;
   Observe(nullptr);
 
+  FOR_EACH_OBSERVER(NativeWindowObserver, observers_,
+                    WillDestoryNativeObject());
+
   // When the web contents is gone, close the window immediately, but the
   // memory will not be freed until you call delete.
   // In this way, it would be safe to manage windows via smart pointers. If you
@@ -611,7 +624,7 @@ void NativeWindow::ScheduleUnresponsiveEvent(int ms) {
 void NativeWindow::NotifyWindowUnresponsive() {
   window_unresposive_closure_.Cancel();
 
-  if (!is_closed_ && !HasModalDialog())
+  if (!is_closed_ && !HasModalDialog() && IsEnabled())
     FOR_EACH_OBSERVER(NativeWindowObserver,
                       observers_,
                       OnRendererUnresponsive());
diff --git a/atom/browser/native_window.h b/atom/browser/native_window.h
index a644682e34..d3b6f8a2b0 100644
--- a/atom/browser/native_window.h
+++ b/atom/browser/native_window.h
@@ -81,7 +81,8 @@ class NativeWindow : public base::SupportsUserData,
   // managing the window's live.
   static NativeWindow* Create(
       brightray::InspectableWebContents* inspectable_web_contents,
-      const mate::Dictionary& options);
+      const mate::Dictionary& options,
+      NativeWindow* parent = nullptr);
 
   // Find a window from its WebContents
   static NativeWindow* FromWebContents(content::WebContents* web_contents);
@@ -97,6 +98,7 @@ class NativeWindow : public base::SupportsUserData,
   virtual void ShowInactive() = 0;
   virtual void Hide() = 0;
   virtual bool IsVisible() = 0;
+  virtual bool IsEnabled() = 0;
   virtual void Maximize() = 0;
   virtual void Unmaximize() = 0;
   virtual bool IsMaximized() = 0;
@@ -158,6 +160,7 @@ class NativeWindow : public base::SupportsUserData,
   virtual void SetFocusable(bool focusable);
   virtual void SetMenu(ui::MenuModel* menu);
   virtual bool HasModalDialog();
+  virtual void SetParentWindow(NativeWindow* parent);
   virtual gfx::NativeWindow GetNativeWindow() = 0;
   virtual gfx::AcceleratedWidget GetAcceleratedWidget() = 0;
 
@@ -255,9 +258,13 @@ class NativeWindow : public base::SupportsUserData,
     has_dialog_attached_ = has_dialog_attached;
   }
 
+  NativeWindow* parent() const { return parent_; }
+  bool is_modal() const { return is_modal_; }
+
  protected:
   NativeWindow(brightray::InspectableWebContents* inspectable_web_contents,
-               const mate::Dictionary& options);
+               const mate::Dictionary& options,
+               NativeWindow* parent);
 
   // Convert draggable regions in raw format to SkRegion format. Caller is
   // responsible for deleting the returned SkRegion instance.
@@ -329,6 +336,12 @@ class NativeWindow : public base::SupportsUserData,
   double aspect_ratio_;
   gfx::Size aspect_ratio_extraSize_;
 
+  // The parent window, it is guaranteed to be valid during this window's life.
+  NativeWindow* parent_;
+
+  // Is this a modal window.
+  bool is_modal_;
+
   // The page this window is viewing.
   brightray::InspectableWebContents* inspectable_web_contents_;
 
diff --git a/atom/browser/native_window_mac.h b/atom/browser/native_window_mac.h
index 899043fd6a..af99b3912e 100644
--- a/atom/browser/native_window_mac.h
+++ b/atom/browser/native_window_mac.h
@@ -22,7 +22,8 @@ namespace atom {
 class NativeWindowMac : public NativeWindow {
  public:
   NativeWindowMac(brightray::InspectableWebContents* inspectable_web_contents,
-                  const mate::Dictionary& options);
+                  const mate::Dictionary& options,
+                  NativeWindow* parent);
   ~NativeWindowMac() override;
 
   // NativeWindow:
@@ -34,6 +35,7 @@ class NativeWindowMac : public NativeWindow {
   void ShowInactive() override;
   void Hide() override;
   bool IsVisible() override;
+  bool IsEnabled() override;
   void Maximize() override;
   void Unmaximize() override;
   bool IsMaximized() override;
@@ -78,6 +80,7 @@ class NativeWindowMac : public NativeWindow {
   bool IsDocumentEdited() override;
   void SetIgnoreMouseEvents(bool ignore) override;
   bool HasModalDialog() override;
+  void SetParentWindow(NativeWindow* parent) override;
   gfx::NativeWindow GetNativeWindow() override;
   gfx::AcceleratedWidget GetAcceleratedWidget() override;
   void SetProgressBar(double progress) override;
@@ -144,9 +147,6 @@ class NativeWindowMac : public NativeWindow {
   // The "titleBarStyle" option.
   TitleBarStyle title_bar_style_;
 
-  // Whether to hide the native toolbar under fullscreen mode.
-  bool should_hide_native_toolbar_in_fullscreen_;
-
   DISALLOW_COPY_AND_ASSIGN(NativeWindowMac);
 };
 
diff --git a/atom/browser/native_window_mac.mm b/atom/browser/native_window_mac.mm
index e15ff0c6ce..5f997ee9b6 100644
--- a/atom/browser/native_window_mac.mm
+++ b/atom/browser/native_window_mac.mm
@@ -429,8 +429,9 @@ namespace atom {
 
 NativeWindowMac::NativeWindowMac(
     brightray::InspectableWebContents* web_contents,
-    const mate::Dictionary& options)
-    : NativeWindow(web_contents, options),
+    const mate::Dictionary& options,
+    NativeWindow* parent)
+    : NativeWindow(web_contents, options, parent),
       is_kiosk_(false),
       attention_request_id_(0),
       title_bar_style_(NORMAL) {
@@ -501,6 +502,11 @@ NativeWindowMac::NativeWindowMac(
   window_delegate_.reset([[AtomNSWindowDelegate alloc] initWithShell:this]);
   [window_ setDelegate:window_delegate_];
 
+  // Only use native parent window for non-modal windows.
+  if (parent && !is_modal()) {
+    SetParentWindow(parent);
+  }
+
   if (transparent()) {
     // Setting the background color to clear will also hide the shadow.
     [window_ setBackgroundColor:[NSColor clearColor]];
@@ -595,6 +601,12 @@ NativeWindowMac::~NativeWindowMac() {
 }
 
 void NativeWindowMac::Close() {
+  // When this is a sheet showing, performClose won't work.
+  if (is_modal() && parent() && IsVisible()) {
+    CloseImmediately();
+    return;
+  }
+
   if (!IsClosable()) {
     WindowList::WindowCloseCancelled(this);
     return;
@@ -624,6 +636,12 @@ bool NativeWindowMac::IsFocused() {
 }
 
 void NativeWindowMac::Show() {
+  if (is_modal() && parent()) {
+    [parent()->GetNativeWindow() beginSheet:window_
+                          completionHandler:^(NSModalResponse) {}];
+    return;
+  }
+
   // This method is supposed to put focus on window, however if the app does not
   // have focus then "makeKeyAndOrderFront" will only show the window.
   [NSApp activateIgnoringOtherApps:YES];
@@ -636,6 +654,12 @@ void NativeWindowMac::ShowInactive() {
 }
 
 void NativeWindowMac::Hide() {
+  if (is_modal() && parent()) {
+    [window_ orderOut:nil];
+    [parent()->GetNativeWindow() endSheet:window_];
+    return;
+  }
+
   [window_ orderOut:nil];
 }
 
@@ -643,6 +667,10 @@ bool NativeWindowMac::IsVisible() {
   return [window_ isVisible];
 }
 
+bool NativeWindowMac::IsEnabled() {
+  return [window_ attachedSheet] == nil;
+}
+
 void NativeWindowMac::Maximize() {
   if (IsMaximized())
     return;
@@ -911,6 +939,21 @@ bool NativeWindowMac::HasModalDialog() {
   return [window_ attachedSheet] != nil;
 }
 
+void NativeWindowMac::SetParentWindow(NativeWindow* parent) {
+  if (is_modal())
+    return;
+
+  NativeWindow::SetParentWindow(parent);
+
+  // Remove current parent window.
+  if ([window_ parentWindow])
+    [[window_ parentWindow] removeChildWindow:window_];
+
+  // Set new current window.
+  if (parent)
+    [parent->GetNativeWindow() addChildWindow:window_ ordered:NSWindowAbove];
+}
+
 gfx::NativeWindow NativeWindowMac::GetNativeWindow() {
   return window_;
 }
@@ -1132,8 +1175,9 @@ void NativeWindowMac::SetCollectionBehavior(bool on, NSUInteger flag) {
 // static
 NativeWindow* NativeWindow::Create(
     brightray::InspectableWebContents* inspectable_web_contents,
-    const mate::Dictionary& options) {
-  return new NativeWindowMac(inspectable_web_contents, options);
+    const mate::Dictionary& options,
+    NativeWindow* parent) {
+  return new NativeWindowMac(inspectable_web_contents, options, parent);
 }
 
 }  // namespace atom
diff --git a/atom/browser/native_window_observer.h b/atom/browser/native_window_observer.h
index 73bf4362f5..16541d0909 100644
--- a/atom/browser/native_window_observer.h
+++ b/atom/browser/native_window_observer.h
@@ -33,6 +33,9 @@ class NativeWindowObserver {
   // Called when the window is gonna closed.
   virtual void WillCloseWindow(bool* prevent_default) {}
 
+  // Called before the native window object is going to be destroyed.
+  virtual void WillDestoryNativeObject() {}
+
   // Called when the window is closed.
   virtual void OnWindowClosed() {}
 
diff --git a/atom/browser/native_window_views.cc b/atom/browser/native_window_views.cc
index 021ceba005..1feb9618ac 100644
--- a/atom/browser/native_window_views.cc
+++ b/atom/browser/native_window_views.cc
@@ -29,6 +29,7 @@
 #include "ui/views/window/client_view.h"
 #include "ui/views/widget/native_widget_private.h"
 #include "ui/views/widget/widget.h"
+#include "ui/wm/core/window_util.h"
 #include "ui/wm/core/shadow_types.h"
 
 #if defined(USE_X11)
@@ -36,6 +37,7 @@
 #include "atom/browser/ui/views/global_menu_bar_x11.h"
 #include "atom/browser/ui/views/frameless_view.h"
 #include "atom/browser/ui/views/native_frame_view.h"
+#include "atom/browser/ui/x/event_disabler.h"
 #include "atom/browser/ui/x/window_state_watcher.h"
 #include "atom/browser/ui/x/x_window_utils.h"
 #include "base/strings/string_util.h"
@@ -125,14 +127,16 @@ class NativeWindowClientView : public views::ClientView {
 
 NativeWindowViews::NativeWindowViews(
     brightray::InspectableWebContents* web_contents,
-    const mate::Dictionary& options)
-    : NativeWindow(web_contents, options),
+    const mate::Dictionary& options,
+    NativeWindow* parent)
+    : NativeWindow(web_contents, options, parent),
       window_(new views::Widget),
       web_view_(inspectable_web_contents()->GetView()->GetView()),
       menu_bar_autohide_(false),
       menu_bar_visible_(false),
       menu_bar_alt_pressed_(false),
       keyboard_event_handler_(new views::UnhandledKeyboardEventHandler),
+      disable_count_(0),
       use_content_size_(false),
       movable_(true),
       resizable_(true),
@@ -186,6 +190,9 @@ NativeWindowViews::NativeWindowViews(
     params.activatable = views::Widget::InitParams::ACTIVATABLE_NO;
 
 #if defined(OS_WIN)
+  if (parent)
+    params.parent = parent->GetNativeWindow();
+
   params.native_widget =
       new views::DesktopNativeWidgetAura(window_.get());
   atom_desktop_window_tree_host_win_ = new AtomDesktopWindowTreeHostWin(
@@ -236,12 +243,23 @@ NativeWindowViews::NativeWindowViews(
     state_atom_list.push_back(GetAtom("_NET_WM_STATE_FULLSCREEN"));
   }
 
+  std::string window_type;
+  options.Get(options::kType, &window_type);
+
+  if (parent) {
+    SetParentWindow(parent);
+    // Force using dialog type for child window.
+    window_type = "dialog";
+    // Modal window needs the _NET_WM_STATE_MODAL hint.
+    if (is_modal())
+      state_atom_list.push_back(GetAtom("_NET_WM_STATE_MODAL"));
+  }
+
   ui::SetAtomArrayProperty(GetAcceleratedWidget(), "_NET_WM_STATE", "ATOM",
                            state_atom_list);
 
   // Set the _NET_WM_WINDOW_TYPE.
-  std::string window_type;
-  if (options.Get(options::kType, &window_type))
+  if (!window_type.empty())
     SetWindowType(GetAcceleratedWidget(), window_type);
 #endif
 
@@ -337,6 +355,9 @@ bool NativeWindowViews::IsFocused() {
 }
 
 void NativeWindowViews::Show() {
+  if (is_modal() && NativeWindow::parent())
+    static_cast<NativeWindowViews*>(NativeWindow::parent())->SetEnabled(false);
+
   window_->native_widget_private()->ShowWithWindowState(GetRestoredState());
 
   NotifyWindowShow();
@@ -359,6 +380,9 @@ void NativeWindowViews::ShowInactive() {
 }
 
 void NativeWindowViews::Hide() {
+  if (is_modal() && NativeWindow::parent())
+    static_cast<NativeWindowViews*>(NativeWindow::parent())->SetEnabled(true);
+
   window_->Hide();
 
   NotifyWindowHide();
@@ -373,6 +397,14 @@ bool NativeWindowViews::IsVisible() {
   return window_->IsVisible();
 }
 
+bool NativeWindowViews::IsEnabled() {
+#if defined(OS_WIN)
+  return ::IsWindowEnabled(GetAcceleratedWidget());
+#elif defined(USE_X11)
+  return !event_disabler_.get();
+#endif
+}
+
 void NativeWindowViews::Maximize() {
   if (IsVisible())
     window_->Maximize();
@@ -772,6 +804,32 @@ void NativeWindowViews::SetMenu(ui::MenuModel* menu_model) {
   Layout();
 }
 
+void NativeWindowViews::SetParentWindow(NativeWindow* parent) {
+  NativeWindow::SetParentWindow(parent);
+
+#if defined(USE_X11)
+  XDisplay* xdisplay = gfx::GetXDisplay();
+  XSetTransientForHint(
+      xdisplay, GetAcceleratedWidget(),
+      parent? parent->GetAcceleratedWidget() : DefaultRootWindow(xdisplay));
+#elif defined(OS_WIN) && defined(DEBUG)
+  // Should work, but does not, it seems that the views toolkit doesn't support
+  // reparenting on desktop.
+  if (parent) {
+    ::SetParent(GetAcceleratedWidget(), parent->GetAcceleratedWidget());
+    views::Widget::ReparentNativeView(GetNativeWindow(),
+                                      parent->GetNativeWindow());
+    wm::AddTransientChild(parent->GetNativeWindow(), GetNativeWindow());
+  } else {
+    if (!GetNativeWindow()->parent())
+      return;
+    ::SetParent(GetAcceleratedWidget(), NULL);
+    views::Widget::ReparentNativeView(GetNativeWindow(), nullptr);
+    wm::RemoveTransientChild(GetNativeWindow()->parent(), GetNativeWindow());
+  }
+#endif
+}
+
 gfx::NativeWindow NativeWindowViews::GetNativeWindow() {
   return window_->GetNativeWindow();
 }
@@ -867,6 +925,33 @@ void NativeWindowViews::SetIcon(const gfx::ImageSkia& icon) {
 }
 #endif
 
+void NativeWindowViews::SetEnabled(bool enable) {
+  // Handle multiple calls of SetEnabled correctly.
+  if (enable) {
+    --disable_count_;
+    if (disable_count_ != 0)
+      return;
+  } else {
+    ++disable_count_;
+    if (disable_count_ != 1)
+      return;
+  }
+
+#if defined(OS_WIN)
+  ::EnableWindow(GetAcceleratedWidget(), enable);
+#elif defined(USE_X11)
+  views::DesktopWindowTreeHostX11* tree_host =
+      views::DesktopWindowTreeHostX11::GetHostForXID(GetAcceleratedWidget());
+  if (enable) {
+    tree_host->RemoveEventRewriter(event_disabler_.get());
+    event_disabler_.reset();
+  } else {
+    event_disabler_.reset(new EventDisabler);
+    tree_host->AddEventRewriter(event_disabler_.get());
+  }
+#endif
+}
+
 void NativeWindowViews::OnWidgetActivationChanged(
     views::Widget* widget, bool active) {
   if (widget != window_.get())
@@ -900,6 +985,15 @@ void NativeWindowViews::OnWidgetBoundsChanged(
 }
 
 void NativeWindowViews::DeleteDelegate() {
+  if (is_modal() && NativeWindow::parent()) {
+    NativeWindowViews* parent =
+        static_cast<NativeWindowViews*>(NativeWindow::parent());
+    // Enable parent window after current window gets closed.
+    parent->SetEnabled(true);
+    // Focus on parent window.
+    parent->Focus(true);
+  }
+
   NotifyWindowClosed();
 }
 
@@ -1110,8 +1204,9 @@ ui::WindowShowState NativeWindowViews::GetRestoredState() {
 // static
 NativeWindow* NativeWindow::Create(
     brightray::InspectableWebContents* inspectable_web_contents,
-    const mate::Dictionary& options) {
-  return new NativeWindowViews(inspectable_web_contents, options);
+    const mate::Dictionary& options,
+    NativeWindow* parent) {
+  return new NativeWindowViews(inspectable_web_contents, options, parent);
 }
 
 }  // namespace atom
diff --git a/atom/browser/native_window_views.h b/atom/browser/native_window_views.h
index 5377420374..69d3d27a35 100644
--- a/atom/browser/native_window_views.h
+++ b/atom/browser/native_window_views.h
@@ -32,6 +32,8 @@ class WindowStateWatcher;
 
 #if defined(OS_WIN)
 class AtomDesktopWindowTreeHostWin;
+#elif defined(USE_X11)
+class EventDisabler;
 #endif
 
 class NativeWindowViews : public NativeWindow,
@@ -42,7 +44,8 @@ class NativeWindowViews : public NativeWindow,
                           public views::WidgetObserver {
  public:
   NativeWindowViews(brightray::InspectableWebContents* inspectable_web_contents,
-                    const mate::Dictionary& options);
+                    const mate::Dictionary& options,
+                    NativeWindow* parent);
   ~NativeWindowViews() override;
 
   // NativeWindow:
@@ -54,6 +57,7 @@ class NativeWindowViews : public NativeWindow,
   void ShowInactive() override;
   void Hide() override;
   bool IsVisible() override;
+  bool IsEnabled() override;
   void Maximize() override;
   void Unmaximize() override;
   bool IsMaximized() override;
@@ -94,6 +98,7 @@ class NativeWindowViews : public NativeWindow,
   void SetIgnoreMouseEvents(bool ignore) override;
   void SetFocusable(bool focusable) override;
   void SetMenu(ui::MenuModel* menu_model) override;
+  void SetParentWindow(NativeWindow* parent) override;
   gfx::NativeWindow GetNativeWindow() override;
   void SetOverlayIcon(const gfx::Image& overlay,
                       const std::string& description) override;
@@ -113,6 +118,8 @@ class NativeWindowViews : public NativeWindow,
   void SetIcon(const gfx::ImageSkia& icon);
 #endif
 
+  void SetEnabled(bool enable);
+
   views::Widget* widget() const { return window_.get(); }
 
 #if defined(OS_WIN)
@@ -187,6 +194,9 @@ class NativeWindowViews : public NativeWindow,
   // Handles window state events.
   std::unique_ptr<WindowStateWatcher> window_state_watcher_;
 
+  // To disable the mouse events.
+  std::unique_ptr<EventDisabler> event_disabler_;
+
   // The "resizable" flag on Linux is implemented by setting size constraints,
   // we need to make sure size constraints are restored when window becomes
   // resizable again.
@@ -220,6 +230,9 @@ class NativeWindowViews : public NativeWindow,
   // Map from accelerator to menu item's command id.
   accelerator_util::AcceleratorTable accelerator_table_;
 
+  // How many times the Disable has been called.
+  int disable_count_;
+
   bool use_content_size_;
   bool movable_;
   bool resizable_;
diff --git a/atom/browser/ui/x/event_disabler.cc b/atom/browser/ui/x/event_disabler.cc
new file mode 100644
index 0000000000..6d0e4cfeb0
--- /dev/null
+++ b/atom/browser/ui/x/event_disabler.cc
@@ -0,0 +1,27 @@
+// Copyright (c) 2016 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#include "atom/browser/ui/x/event_disabler.h"
+
+namespace atom {
+
+EventDisabler::EventDisabler() {
+}
+
+EventDisabler::~EventDisabler() {
+}
+
+ui::EventRewriteStatus EventDisabler::RewriteEvent(
+    const ui::Event& event,
+    std::unique_ptr<ui::Event>* rewritten_event) {
+  return ui::EVENT_REWRITE_DISCARD;
+}
+
+ui::EventRewriteStatus EventDisabler::NextDispatchEvent(
+    const ui::Event& last_event,
+    std::unique_ptr<ui::Event>* new_event) {
+  return ui::EVENT_REWRITE_CONTINUE;
+}
+
+}  // namespace atom
diff --git a/atom/browser/ui/x/event_disabler.h b/atom/browser/ui/x/event_disabler.h
new file mode 100644
index 0000000000..9a6645bcdc
--- /dev/null
+++ b/atom/browser/ui/x/event_disabler.h
@@ -0,0 +1,32 @@
+// Copyright (c) 2016 GitHub, Inc.
+// Use of this source code is governed by the MIT license that can be
+// found in the LICENSE file.
+
+#ifndef ATOM_BROWSER_UI_X_EVENT_DISABLER_H_
+#define ATOM_BROWSER_UI_X_EVENT_DISABLER_H_
+
+#include "base/macros.h"
+#include "ui/events/event_rewriter.h"
+
+namespace atom {
+
+class EventDisabler : public ui::EventRewriter {
+ public:
+  EventDisabler();
+  ~EventDisabler() override;
+
+  // ui::EventRewriter:
+  ui::EventRewriteStatus RewriteEvent(
+      const ui::Event& event,
+      std::unique_ptr<ui::Event>* rewritten_event) override;
+  ui::EventRewriteStatus NextDispatchEvent(
+      const ui::Event& last_event,
+      std::unique_ptr<ui::Event>* new_event) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(EventDisabler);
+};
+
+}  // namespace atom
+
+#endif  // ATOM_BROWSER_UI_X_EVENT_DISABLER_H_
diff --git a/atom/common/key_weak_map.h b/atom/common/key_weak_map.h
index bce34bfe0f..009ba099c9 100644
--- a/atom/common/key_weak_map.h
+++ b/atom/common/key_weak_map.h
@@ -14,10 +14,6 @@
 
 namespace atom {
 
-namespace internal {
-
-}  // namespace internal
-
 // Like ES6's WeakMap, but the key is Integer and the value is Weak Pointer.
 template<typename K>
 class KeyWeakMap {
@@ -57,7 +53,7 @@ class KeyWeakMap {
   }
 
   // Returns all objects.
-  std::vector<v8::Local<v8::Object>> Values(v8::Isolate* isolate) {
+  std::vector<v8::Local<v8::Object>> Values(v8::Isolate* isolate) const {
     std::vector<v8::Local<v8::Object>> keys;
     keys.reserve(map_.size());
     for (const auto& iter : map_) {
diff --git a/docs/api/browser-window.md b/docs/api/browser-window.md
index 6aae7b0080..e95570450b 100644
--- a/docs/api/browser-window.md
+++ b/docs/api/browser-window.md
@@ -59,6 +59,39 @@ win.loadURL('https://github.com')
 Note that even for apps that use `ready-to-show` event, it is still recommended
 to set `backgroundColor` to make app feel more native.
 
+## Parent and child windows
+
+By using `parent` option, you can create child windows:
+
+```javascript
+let top = new BrowserWindow()
+let child = new BrowserWindow({parent: top})
+```
+
+The `child` window will always show on top of the `top` window.
+
+### Modal windows
+
+A modal window is a child window that disables parent window, to create a modal
+window, you have to set both `parent` and `modal` options:
+
+```javascript
+let child = new BrowserWindow({parent: top, modal: true, show: false})
+child.loadURL('https://github.com')
+child.once('ready-to-show', () => {
+  child.show()
+})
+```
+
+### Platform notices
+
+* On macOS the child windows will keep the relative position to parent window
+  when parent window moves, while on Windows and Linux child windows will not
+  move.
+* On Windows it is not supported to change parent window dynamically.
+* On Linux the type of modal windows will be changed to `dialog`.
+* On Linux many desktop environments do not support hiding a modal window.
+
 ## Class: BrowserWindow
 
 `BrowserWindow` is an
@@ -116,6 +149,9 @@ It creates a new `BrowserWindow` with native properties as set by the `options`.
     `true`.
   * `frame` Boolean - Specify `false` to create a
     [Frameless Window](frameless-window.md). Default is `true`.
+  * `parent` BrowserWindow - Specify parent window. Default is `null`.
+  * `modal` Boolean - Whether this is a modal window. This only works when the
+    window is a child window. Default is `false`.
   * `acceptFirstMouse` Boolean - Whether the web view accepts a single
     mouse-down event that simultaneously activates the window. Default is
     `false`.
@@ -532,6 +568,10 @@ Hides the window.
 
 Returns a boolean, whether the window is visible to the user.
 
+### `win.isModal()`
+
+Returns whether current window is a modal window.
+
 ### `win.maximize()`
 
 Maximizes the window.
@@ -1017,3 +1057,18 @@ events.
 Changes whether the window can be focused.
 
 [blink-feature-string]: https://cs.chromium.org/chromium/src/third_party/WebKit/Source/platform/RuntimeEnabledFeatures.in
+
+### `win.setParentWindow(parent)` _Linux_ _macOS_
+
+* `parent` BrowserWindow
+
+Sets `parent` as current window's parent window, passing `null` will turn
+current window into a top-level window.
+
+### `win.getParentWindow()`
+
+Returns the parent window.
+
+### `win.getChildWindows()`
+
+Returns all child windows.
diff --git a/filenames.gypi b/filenames.gypi
index 87ff5dc981..af7080821b 100644
--- a/filenames.gypi
+++ b/filenames.gypi
@@ -286,6 +286,8 @@
       'atom/browser/ui/win/notify_icon.h',
       'atom/browser/ui/win/taskbar_host.cc',
       'atom/browser/ui/win/taskbar_host.h',
+      'atom/browser/ui/x/event_disabler.cc',
+      'atom/browser/ui/x/event_disabler.h',
       'atom/browser/ui/x/window_state_watcher.cc',
       'atom/browser/ui/x/window_state_watcher.h',
       'atom/browser/ui/x/x_window_utils.cc',
diff --git a/lib/browser/api/browser-window.js b/lib/browser/api/browser-window.js
index 0847649956..388e396844 100644
--- a/lib/browser/api/browser-window.js
+++ b/lib/browser/api/browser-window.js
@@ -117,7 +117,6 @@ BrowserWindow.fromDevToolsWebContents = (webContents) => {
 }
 
 // Helpers.
-
 Object.assign(BrowserWindow.prototype, {
   loadURL (...args) {
     return this.webContents.loadURL.apply(this.webContents, args)
diff --git a/spec/api-browser-window-spec.js b/spec/api-browser-window-spec.js
index 598a3470f7..7310cd6a90 100644
--- a/spec/api-browser-window-spec.js
+++ b/spec/api-browser-window-spec.js
@@ -836,6 +836,110 @@ describe('browser-window module', function () {
     })
   })
 
+  describe('parent window', function () {
+    let c = null
+
+    beforeEach(function () {
+      if (c != null) c.destroy()
+      c = new BrowserWindow({show: false, parent: w})
+    })
+
+    afterEach(function () {
+      if (c != null) c.destroy()
+      c = null
+    })
+
+    describe('parent option', function () {
+      it('sets parent window', function () {
+        assert.equal(c.getParentWindow(), w)
+      })
+
+      it('adds window to child windows of parent', function () {
+        assert.deepEqual(w.getChildWindows(), [c])
+      })
+
+      it('removes from child windows of parent when window is closed', function (done) {
+        c.once('closed', () => {
+          assert.deepEqual(w.getChildWindows(), [])
+          done()
+        })
+        c.close()
+      })
+    })
+
+    describe('win.setParentWindow(parent)', function () {
+      if (process.platform === 'win32') return
+
+      beforeEach(function () {
+        if (c != null) c.destroy()
+        c = new BrowserWindow({show: false})
+      })
+
+      it('sets parent window', function () {
+        assert.equal(w.getParentWindow(), null)
+        assert.equal(c.getParentWindow(), null)
+        c.setParentWindow(w)
+        assert.equal(c.getParentWindow(), w)
+        c.setParentWindow(null)
+        assert.equal(c.getParentWindow(), null)
+      })
+
+      it('adds window to child windows of parent', function () {
+        assert.deepEqual(w.getChildWindows(), [])
+        c.setParentWindow(w)
+        assert.deepEqual(w.getChildWindows(), [c])
+        c.setParentWindow(null)
+        assert.deepEqual(w.getChildWindows(), [])
+      })
+
+      it('removes from child windows of parent when window is closed', function (done) {
+        c.once('closed', () => {
+          assert.deepEqual(w.getChildWindows(), [])
+          done()
+        })
+        c.setParentWindow(w)
+        c.close()
+      })
+    })
+
+    describe('modal option', function () {
+      // The isEnabled API is not reliable on macOS.
+      if (process.platform === 'darwin') return
+
+      beforeEach(function () {
+        if (c != null) c.destroy()
+        c = new BrowserWindow({show: false, parent: w, modal: true})
+      })
+
+      it('disables parent window', function () {
+        assert.equal(w.isEnabled(), true)
+        c.show()
+        assert.equal(w.isEnabled(), false)
+      })
+
+      it('enables parent window when closed', function (done) {
+        c.once('closed', () => {
+          assert.equal(w.isEnabled(), true)
+          done()
+        })
+        c.show()
+        c.close()
+      })
+
+      it('disables parent window recursively', function () {
+        let c2 = new BrowserWindow({show: false, parent: w, modal: true})
+        c.show()
+        assert.equal(w.isEnabled(), false)
+        c2.show()
+        assert.equal(w.isEnabled(), false)
+        c.destroy()
+        assert.equal(w.isEnabled(), false)
+        c2.destroy()
+        assert.equal(w.isEnabled(), true)
+      })
+    })
+  })
+
   describe('window.webContents.send(channel, args...)', function () {
     it('throws an error when the channel is missing', function () {
       assert.throws(function () {