diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 9fc16bfde..bc07a197f 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -5112,6 +5112,7 @@ run_test    "DTLS fragmenting: both (MTU)" \
             -C "error"
 
 # Test for automatic MTU reduction on repeated resend
+not_with_valgrind
 requires_config_enabled MBEDTLS_SSL_PROTO_DTLS
 requires_config_enabled MBEDTLS_RSA_C
 requires_config_enabled MBEDTLS_ECDSA_C