diff --git a/configure.ac b/configure.ac
index 884ff3122a..21f81ce9e9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -13024,6 +13024,10 @@ fi
 if test "$ENABLED_ARC4" = "yes"
 then
     AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_ALLOW_RC4"
+    if test "$ENABLED_TLS" != "no"
+    then
+        AC_MSG_WARN([RC4 cipher suites are built into this TLS configuration. RFC 7465 prohibits RC4 in TLS, and RFC 8446 Appendix D.5 says a TLS 1.3 capable implementation MUST NOT offer or negotiate RC4 in any protocol version. Use --disable-arc4 unless RC4 is required.])
+    fi
 fi