diff --git a/Lib/lib2to3/fixes/fix_types.py b/Lib/lib2to3/fixes/fix_types.py
index db341047855..00327a78e8e 100644
--- a/Lib/lib2to3/fixes/fix_types.py
+++ b/Lib/lib2to3/fixes/fix_types.py
@@ -42,7 +42,7 @@
         'NotImplementedType' : 'type(NotImplemented)',
         'SliceType' : 'slice',
         'StringType': 'bytes', # XXX ?
-        'StringTypes' : 'str', # XXX ?
+        'StringTypes' : '(str,)', # XXX ?
         'TupleType': 'tuple',
         'TypeType' : 'type',
         'UnicodeType': 'str',
diff --git a/Lib/lib2to3/tests/test_fixers.py b/Lib/lib2to3/tests/test_fixers.py
index 06b0033b8f7..def9b0e47a5 100644
--- a/Lib/lib2to3/tests/test_fixers.py
+++ b/Lib/lib2to3/tests/test_fixers.py
@@ -3322,6 +3322,10 @@ def test_basic_types_convert(self):
         a = """type(None)"""
         self.check(b, a)
 
+        b = "types.StringTypes"
+        a = "(str,)"
+        self.check(b, a)
+
 class Test_idioms(FixerTestCase):
     fixer = "idioms"
 
diff --git a/Misc/NEWS b/Misc/NEWS
index ce0bd5654c4..f2f7599bde0 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,6 +13,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #13938: 2to3 converts StringTypes to a tuple. Patch from Mark Hammond.
+
 - Issue #8585: improved tests for zipimporter2. Patch from Mark Lawrence.
 
 - Issue #18622: unittest.mock.mock_open().reset_mock would recurse infinitely.