diff --git a/spec/app/root-view-spec.coffee b/spec/app/root-view-spec.coffee
index dd813d138..ce676c4ec 100644
--- a/spec/app/root-view-spec.coffee
+++ b/spec/app/root-view-spec.coffee
@@ -470,3 +470,10 @@ describe "RootView", ->
       expect(rootView.getFontSize()).toBe fontSizeBefore + 1
       rootView.trigger 'decrease-font-size'
       expect(rootView.getFontSize()).toBe fontSizeBefore
+
+  it "does not allow the font size to be less than 1", ->
+    rootView.setFontSize(1)
+    expect(rootView.getFontSize()).toBe 1
+
+    rootView.setFontSize(0)
+    expect(rootView.getFontSize()).toBe 1
diff --git a/src/app/root-view.coffee b/src/app/root-view.coffee
index 9bc9c7eff..6fdeac5f3 100644
--- a/src/app/root-view.coffee
+++ b/src/app/root-view.coffee
@@ -155,6 +155,7 @@ class RootView extends View
     super
 
   setFontSize: (newFontSize) ->
+    newFontSize = Math.max(1, newFontSize)
     [oldFontSize, @fontSize] = [@fontSize, newFontSize]
     @trigger 'font-size-change' if oldFontSize != newFontSize