diff --git a/Lib/ctypes/util.py b/Lib/ctypes/util.py
index adde30798ca2..52b35206145f 100644
--- a/Lib/ctypes/util.py
+++ b/Lib/ctypes/util.py
@@ -185,7 +185,7 @@ def find_library(name):
         def _findLib_ldconfig(name):
             # XXX assuming GLIBC's ldconfig (with option -p)
             expr = r'/[^\(\)\s]*lib%s\.[^\(\)\s]*' % re.escape(name)
-            f = os.popen('LANG=C /sbin/ldconfig -p 2>/dev/null')
+            f = os.popen('LC_ALL=C LANG=C /sbin/ldconfig -p 2>/dev/null')
             try:
                 data = f.read()
             finally: