diff --git a/include/mbedtls/gcm.h b/include/mbedtls/gcm.h
index 00ed421..bd258aa 100644
--- a/include/mbedtls/gcm.h
+++ b/include/mbedtls/gcm.h
@@ -31,6 +31,12 @@
 #ifndef MBEDTLS_GCM_H
 #define MBEDTLS_GCM_H
 
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
 #include "cipher.h"
 
 #include <stdint.h>