diff --git a/cpplint/cpplint.py b/cpplint/cpplint.py
index 7ca3862..b5493b6 100755
--- a/cpplint/cpplint.py
+++ b/cpplint/cpplint.py
@@ -2681,8 +2681,11 @@
           'Missing spaces around %s' % match.group(1))
   # We allow no-spaces around << when used like this: 10<<20, but
   # not otherwise (particularly, not when used as streams)
-  match = Search(r'(\S)(?:L|UL|ULL|l|ul|ull)?<<(\S)', line)
-  if match and not (match.group(1).isdigit() and match.group(2).isdigit()):
+  # Also ignore using ns::operator<<;
+  match = Search(r'(operator|\S)(?:L|UL|ULL|l|ul|ull)?<<(\S)', line)
+  if (match and
+      not (match.group(1).isdigit() and match.group(2).isdigit()) and
+      not (match.group(1) == 'operator' and match.group(2) == ';')):
     error(filename, linenum, 'whitespace/operators', 3,
           'Missing spaces around <<')
   elif not Match(r'#.*include', line):