diff --git a/Tests/images/hopper_zero_comment_subblocks.gif b/Tests/images/hopper_zero_comment_subblocks.gif
new file mode 100644
index 000000000..5f482c042
Binary files /dev/null and b/Tests/images/hopper_zero_comment_subblocks.gif differ
diff --git a/Tests/test_file_gif.py b/Tests/test_file_gif.py
index cfa1bb1e7..ffaff7afe 100644
--- a/Tests/test_file_gif.py
+++ b/Tests/test_file_gif.py
@@ -435,6 +435,11 @@ class TestFileGif(PillowTestCase):
 
         self.assertEqual(reread.info['comment'], im.info['comment'])
 
+    def test_zero_comment_subblocks(self):
+        im = Image.open('Tests/images/hopper_zero_comment_subblocks.gif')
+        expected = Image.open(TEST_GIF)
+        self.assert_image_equal(im, expected)
+
     def test_version(self):
         out = self.tempfile('temp.gif')
 
diff --git a/src/PIL/GifImagePlugin.py b/src/PIL/GifImagePlugin.py
index ecd993cd5..f8d42e6fd 100644
--- a/src/PIL/GifImagePlugin.py
+++ b/src/PIL/GifImagePlugin.py
@@ -202,6 +202,8 @@ class GifImageFile(ImageFile.ImageFile):
                     # comment extension
                     #
                     info["comment"] = block
+                    if not block:
+                        continue
                 elif i8(s) == 255:
                     #
                     # application extension