diff --git a/include/mbedtls/hkdf.h b/include/mbedtls/hkdf.h
index e6ed7cd..40ee64e 100644
--- a/include/mbedtls/hkdf.h
+++ b/include/mbedtls/hkdf.h
@@ -27,6 +27,12 @@
 #ifndef MBEDTLS_HKDF_H
 #define MBEDTLS_HKDF_H
 
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
 #include "md.h"
 
 /**