diff --git a/include/mbedtls/md.h b/include/mbedtls/md.h
index fa2b152f96..34f314f3f4 100644
--- a/include/mbedtls/md.h
+++ b/include/mbedtls/md.h
@@ -74,6 +74,10 @@ typedef enum {
 #define MBEDTLS_MD_MAX_BLOCK_SIZE         64
 #endif
 
+#if defined(MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL)
+#define MBEDTLS_TLS1_3_MD_MAX_SIZE         MBEDTLS_MD_MAX_SIZE
+#endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */
+
 /**
  * Opaque struct.
  *
diff --git a/library/ssl_misc.h b/library/ssl_misc.h
index d194b0e1eb..b8361dbb65 100644
--- a/library/ssl_misc.h
+++ b/library/ssl_misc.h
@@ -678,9 +678,9 @@ struct mbedtls_ssl_handshake_params
 
     union
     {
-        unsigned char early    [MBEDTLS_MD_MAX_SIZE];
-        unsigned char handshake[MBEDTLS_MD_MAX_SIZE];
-        unsigned char app      [MBEDTLS_MD_MAX_SIZE];
+        unsigned char early    [MBEDTLS_TLS1_3_MD_MAX_SIZE];
+        unsigned char handshake[MBEDTLS_TLS1_3_MD_MAX_SIZE];
+        unsigned char app      [MBEDTLS_TLS1_3_MD_MAX_SIZE];
     } tls1_3_master_secrets;
 #endif /* MBEDTLS_SSL_PROTO_TLS1_3_EXPERIMENTAL */