diff --git a/Lib/fontTools/ufoLib/__init__.py b/Lib/fontTools/ufoLib/__init__.py
index 9b47f70ec..38e44ecd7 100755
--- a/Lib/fontTools/ufoLib/__init__.py
+++ b/Lib/fontTools/ufoLib/__init__.py
@@ -459,7 +459,12 @@ class UFOReader(_UFOBaseIO):
 	# groups.plist
 
 	def _readGroups(self):
-		return self._getPlist(GROUPS_FILENAME, {})
+		groups = self._getPlist(GROUPS_FILENAME, {})
+		# remove any duplicate glyphs in a kerning group
+		for groupName, glyphList in groups.items():
+			if groupName.startswith('public.kern1.') or groupName.startswith('public.kern2.'):
+				groups[groupName] = list(OrderedDict.fromkeys(glyphList))
+		return groups
 
 	def readGroups(self, validate=None):
 		"""
@@ -476,10 +481,6 @@ class UFOReader(_UFOBaseIO):
 		# normal
 		else:
 			groups = self._readGroups()
-			# remove any duplicate glyphs in a kerning group
-			for groupName, glyphList in groups.items():
-				if groupName.startswith('public.kern1.') or groupName.startswith('public.kern2.'):
-					glyphList = list(OrderedDict.fromkeys(glyphList))
 		if validate:
 			valid, message = groupsValidator(groups)
 			if not valid:
diff --git a/Tests/ufoLib/UFO3_test.py b/Tests/ufoLib/UFO3_test.py
index 30faf2ee1..28f5ea191 100644
--- a/Tests/ufoLib/UFO3_test.py
+++ b/Tests/ufoLib/UFO3_test.py
@@ -4192,6 +4192,20 @@ class UFO3ReadDataTestCase(unittest.TestCase):
 		fileObject = reader.getReadFileForPath("data/org.unifiedfontobject.doesNotExist")
 		self.assertEqual(fileObject, None)
 
+	def testUFOReaderGroupDuplicatesRemoved(self):
+		# Non-kerning group duplicates are kept
+		# Kerning group duplicates are removed
+		expected_groups = {
+			"group1" : ["A"],
+			"group2" : ["B", "B"],
+			"public.kern1.A" : ["A"],
+			"public.kern2.B" : ["B"],
+		}
+		reader = UFOReader(self.getFontPath())
+		groups = reader.readGroups()
+		import pdb; pdb.set_trace()
+		self.assertEqual(expected_groups, groups)
+
 
 class UFO3WriteDataTestCase(unittest.TestCase):
 
diff --git a/Tests/ufoLib/testdata/UFO3-Read Data.ufo/groups.plist b/Tests/ufoLib/testdata/UFO3-Read Data.ufo/groups.plist
new file mode 100644
index 000000000..8564bcd9e
--- /dev/null
+++ b/Tests/ufoLib/testdata/UFO3-Read Data.ufo/groups.plist	
@@ -0,0 +1,24 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple Computer//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>group1</key>
+	<array>
+		<string>A</string>
+	</array>
+	<key>group2</key>
+	<array>
+		<string>B</string>
+		<string>B</string>
+	</array>
+	<key>public.kern1.A</key>
+	<array>
+		<string>A</string>
+	</array>
+	<key>public.kern2.B</key>
+	<array>
+		<string>B</string>
+		<string>B</string>
+	</array>
+</dict>
+</plist>