diff --git a/clang/tools/clang-format/clang-format.py b/clang/tools/clang-format/clang-format.py
--- a/clang/tools/clang-format/clang-format.py
+++ b/clang/tools/clang-format/clang-format.py
@@ -10,9 +10,9 @@
 #     imap <C-I> <c-o>:py3f <path-to-this-file>/clang-format.py<cr>
 #   endif
 #
-# The if-elseif-endif conditional should pick either the python3 or python2 
+# The if-elseif-endif conditional should pick either the python3 or python2
 # integration depending on your vim setup.
-# 
+#
 # The first mapping enables clang-format for NORMAL and VISUAL mode, the second
 # mapping adds support for INSERT mode. Change "C-I" to another binding if you
 # need clang-format on a different key (C-I stands for Ctrl+i).
@@ -134,7 +134,7 @@
     )
   else:
     header, content = stdout.split(b'\n', 1)
-    header = json.loads(header)
+    header = json.loads(header.decode('utf-8'))
     # Strip off the trailing newline (added above).
     # This maintains trailing empty lines present in the buffer if
     # the -lines specification requests them to remain unchanged.