diff --git a/libcxx/test/lit.cfg b/libcxx/test/lit.cfg
index 5e64e54de35f..4b7b4705978a 100644
--- a/libcxx/test/lit.cfg
+++ b/libcxx/test/lit.cfg
@@ -71,7 +71,7 @@ class LibcxxTestFormat(lit.formats.FileBasedTest):
                 elif 'REQUIRES:' in ln:
                     items = ln[ln.index('REQUIRES:') + 9:].split(',')
                     requires.extend([s.strip() for s in items])
-                elif not ln.startswith("//") and ln.strip():
+                elif not ln.strip().startswith("//") and ln.strip():
                     # Stop at the first non-empty line that is not a C++
                     # comment.
                     break