diff --git a/bin/tests/system/run.sh.in b/bin/tests/system/run.sh.in
index d06f587732..084efc47d8 100644
--- a/bin/tests/system/run.sh.in
+++ b/bin/tests/system/run.sh.in
@@ -78,7 +78,7 @@ if ! $do_run; then
         SYSTEMTEST_FORCE_COLOR="$SYSTEMTEST_FORCE_COLOR" \
         SYSTEMTEST_NO_CLEAN="$SYSTEMTEST_NO_CLEAN" \
         SLOT="$SLOT" \
-        OPENSSL_CONF="$OPENSSL_CONF" \
+        ${OPENSSL_CONF:+OPENSSL_CONF="$OPENSSL_CONF"} \
         SOFTHSM2_CONF="$SOFTHSM2_CONF" \
         SOFTHSM2_MODULE="$SOFTHSM2_MODULE" \
         PATH="$PATH" \