diff --git a/hacking/core.py b/hacking/core.py
index e63df3e..3e80ab3 100755
--- a/hacking/core.py
+++ b/hacking/core.py
@@ -856,7 +856,7 @@ class GitCheck(GlobalCheck):
         try:
             subp = subprocess.Popen(
                 ['git', 'rev-parse', '--show-toplevel'],
-                stdout=subprocess.PIPE)
+                stdout=subprocess.PIPE, stderr=subprocess.PIPE)
             gitdir = subp.communicate()[0].rstrip()
         except OSError:
             # "git" was not found