diff --git a/include/mbedtls/cmac.h b/include/mbedtls/cmac.h
index 24839a2..adfe1c3 100644
--- a/include/mbedtls/cmac.h
+++ b/include/mbedtls/cmac.h
@@ -26,6 +26,12 @@
 #ifndef MBEDTLS_CMAC_H
 #define MBEDTLS_CMAC_H
 
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
 #include "cipher.h"
 
 #ifdef __cplusplus