diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index dadadf546..bd36e227b 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -3233,6 +3233,7 @@ run_test    "DTLS proxy: 3d, min handshake, server-initiated renego, nbio" \
             -c "HTTP/1.0 200 OK"
 
 needs_more_time 6
+not_with_valgrind # risk of non-mbedtls peer timing out
 run_test    "DTLS proxy: 3d, openssl server" \
             -p "$P_PXY drop=5 delay=5 duplicate=5 protect_hvr=1" \
             "$O_SRV -dtls1 -mtu 2048" \
@@ -3241,6 +3242,7 @@ run_test    "DTLS proxy: 3d, openssl server" \
             -c "HTTP/1.0 200 OK"
 
 needs_more_time 8
+not_with_valgrind # risk of non-mbedtls peer timing out
 run_test    "DTLS proxy: 3d, openssl server, fragmentation" \
             -p "$P_PXY drop=5 delay=5 duplicate=5 protect_hvr=1" \
             "$O_SRV -dtls1 -mtu 768" \
@@ -3249,6 +3251,7 @@ run_test    "DTLS proxy: 3d, openssl server, fragmentation" \
             -c "HTTP/1.0 200 OK"
 
 needs_more_time 8
+not_with_valgrind # risk of non-mbedtls peer timing out
 run_test    "DTLS proxy: 3d, openssl server, fragmentation, nbio" \
             -p "$P_PXY drop=5 delay=5 duplicate=5 protect_hvr=1" \
             "$O_SRV -dtls1 -mtu 768" \
@@ -3258,6 +3261,7 @@ run_test    "DTLS proxy: 3d, openssl server, fragmentation, nbio" \
 
 requires_gnutls
 needs_more_time 6
+not_with_valgrind # risk of non-mbedtls peer timing out
 run_test    "DTLS proxy: 3d, gnutls server" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$G_SRV -u --mtu 2048 -a" \
@@ -3268,6 +3272,7 @@ run_test    "DTLS proxy: 3d, gnutls server" \
 
 requires_gnutls
 needs_more_time 8
+not_with_valgrind # risk of non-mbedtls peer timing out
 run_test    "DTLS proxy: 3d, gnutls server, fragmentation" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$G_SRV -u --mtu 512" \
@@ -3278,6 +3283,7 @@ run_test    "DTLS proxy: 3d, gnutls server, fragmentation" \
 
 requires_gnutls
 needs_more_time 8
+not_with_valgrind # risk of non-mbedtls peer timing out
 run_test    "DTLS proxy: 3d, gnutls server, fragmentation, nbio" \
             -p "$P_PXY drop=5 delay=5 duplicate=5" \
             "$G_SRV -u --mtu 512" \