diff --git a/include/openssl/bn.h b/include/openssl/bn.h
index 0d2068f..bdd41ba 100644
--- a/include/openssl/bn.h
+++ b/include/openssl/bn.h
@@ -938,7 +938,7 @@
 #if defined(__cplusplus)
 }  /* extern C */
 
-#if !defined(OPENSSL_NO_CXX)
+#if !defined(BORINGSSL_NO_CXX)
 extern "C++" {
 
 namespace bssl {