diff --git a/lib/mbedtls/mbedtls_def_config.h b/lib/mbedtls/mbedtls_def_config.h
index 1d2314e..fd440c3 100644
--- a/lib/mbedtls/mbedtls_def_config.h
+++ b/lib/mbedtls/mbedtls_def_config.h
@@ -56,6 +56,10 @@
 #endif
 #endif
 
+#if CONFIG_IS_ENABLED(HKDF_MBEDTLS)
+#define MBEDTLS_HKDF_C
+#endif
+
 #if defined CONFIG_MBEDTLS_LIB_X509
 
 #if CONFIG_IS_ENABLED(X509_CERTIFICATE_PARSER)