diff --git a/src/app/text-buffer.coffee b/src/app/text-buffer.coffee
index cc1cc1901..2a20ea1cc 100644
--- a/src/app/text-buffer.coffee
+++ b/src/app/text-buffer.coffee
@@ -587,7 +587,7 @@ class Buffer
   # startIndex - The starting row {Number}
   # endIndex - The ending row {Number}
   #
-  # Returns an {Array} of {RegExp}s, representing the matches
+  # Returns an {Array} of {RegExp}s, representing the matches.
   matchesInCharacterRange: (regex, startIndex, endIndex) ->
     text = @getText()
     matches = []
diff --git a/src/packages/whitespace/lib/whitespace.coffee b/src/packages/whitespace/lib/whitespace.coffee
index a16f9877b..1a68b1971 100644
--- a/src/packages/whitespace/lib/whitespace.coffee
+++ b/src/packages/whitespace/lib/whitespace.coffee
@@ -9,7 +9,10 @@ module.exports =
     buffer = editSession.buffer
     buffer.on 'will-be-saved', ->
       buffer.transact ->
-        buffer.scan /[ \t]+$/g, ({replace}) -> replace('')
+        buffer.scan /[ \t]+$/g, ({match, replace}) ->
+          # GFM permits two whitespaces at the end of a line--trim anything else
+          unless editSession.getGrammar().scopeName is "source.gfm" and match[0] is "  "
+            replace('')
 
         if config.get('whitespace.ensureSingleTrailingNewline')
           if buffer.getLastLine() is ''
diff --git a/src/packages/whitespace/spec/whitespace-spec.coffee b/src/packages/whitespace/spec/whitespace-spec.coffee
index 35fe6a8ee..ab7146846 100644
--- a/src/packages/whitespace/spec/whitespace-spec.coffee
+++ b/src/packages/whitespace/spec/whitespace-spec.coffee
@@ -86,3 +86,30 @@ describe "Whitespace", ->
       editor.getBuffer().save()
       expect(editor.getText()).toBe "foo\n"
       expect(editor.getCursorBufferPosition()).toEqual([0,3])
+
+  describe "GFM whitespace trimming", ->
+    grammar = null
+
+    beforeEach ->
+      spyOn(syntax, "addGrammar").andCallThrough()
+      atom.activatePackage("gfm")
+      expect(syntax.addGrammar).toHaveBeenCalled()
+      grammar = syntax.addGrammar.argsForCall[0][0]
+
+    it "trims GFM text with a single space", ->
+      editor.activeEditSession.setGrammar(grammar)
+      editor.insertText "foo \nline break!"
+      editor.getBuffer().save()
+      expect(editor.getText()).toBe "foo\nline break!\n"
+
+    it "leaves GFM text with double spaces alone", ->
+      editor.activeEditSession.setGrammar(grammar)
+      editor.insertText "foo  \nline break!"
+      editor.getBuffer().save()
+      expect(editor.getText()).toBe "foo  \nline break!\n"
+
+    it "trims GFM text with a more than two spaces", ->
+      editor.activeEditSession.setGrammar(grammar)
+      editor.insertText "foo   \nline break!"
+      editor.getBuffer().save()
+      expect(editor.getText()).toBe "foo\nline break!\n"