diff --git a/tests/util/grub-shell-luks-tester.in b/tests/util/grub-shell-luks-tester.in
index 3f9d1be17..8926cbc96 100644
--- a/tests/util/grub-shell-luks-tester.in
+++ b/tests/util/grub-shell-luks-tester.in
@@ -38,6 +38,7 @@ keyfile_size=
 KEYFILE_SIZE_MAX=4096
 
 debug="${GRUB_SHELL_LUKS_DEFAULT_DEBUG:-$GRUB_TEST_DEFAULT_DEBUG}"
+GRUB_SHELL_LUKS_TIMEOUT=${GRUB_SHELL_LUKS_TIMEOUT:-${GRUB_SHELL_DEFAULT_TIMEOUT:-600s}}
 
 # Usage: usage
 # Print the usage.
@@ -134,7 +135,7 @@ done
 
 [ "${debug:-0}" -gt 1 ] && set -x
 
-grub_shell_opts="$grub_shell_opts --timeout=600s"
+grub_shell_opts="$grub_shell_opts --timeout=${GRUB_SHELL_LUKS_TIMEOUT}"
 
 if [ "${debug:-0}" -gt 2 ]; then
     grub_shell_opts="$grub_shell_opts --qemu-opts=-nographic"