diff --git a/spec/text-editor-spec.coffee b/spec/text-editor-spec.coffee
index 7ca01f290..4dc035f07 100644
--- a/spec/text-editor-spec.coffee
+++ b/spec/text-editor-spec.coffee
@@ -4335,6 +4335,13 @@ describe "TextEditor", ->
           editor.toggleLineCommentsInSelection()
           expect(buffer.lineForRow(4)).toBe "    while(items.length > 0) {"
 
+      it "does nothing for empty lines and null grammar", ->
+        runs ->
+          editor.setGrammar(atom.grammars.grammarForScopeName('text.plain.null-grammar'))
+          editor.setCursorBufferPosition([10, 0])
+          editor.toggleLineCommentsInSelection()
+          expect(editor.buffer.lineForRow(10)).toBe ""
+
       it "uncomments when the line lacks the trailing whitespace in the comment regex", ->
         editor.setCursorBufferPosition([10, 0])
         editor.toggleLineCommentsInSelection()
diff --git a/src/language-mode.coffee b/src/language-mode.coffee
index bb9f339c4..06990bad5 100644
--- a/src/language-mode.coffee
+++ b/src/language-mode.coffee
@@ -27,7 +27,7 @@ class LanguageMode
   toggleLineCommentsForBufferRows: (start, end) ->
     scope = @editor.scopeDescriptorForBufferPosition([start, 0])
     commentStrings = @editor.getCommentStrings(scope)
-    return unless commentStrings?
+    return unless commentStrings?.commentStartString
     {commentStartString, commentEndString} = commentStrings
 
     buffer = @editor.buffer