diff --git a/.gitlab-ci/thorough-test-wrapper.sh b/.gitlab-ci/thorough-test-wrapper.sh
new file mode 100644
index 000000000..2bb149ed8
--- /dev/null
+++ b/.gitlab-ci/thorough-test-wrapper.sh
@@ -0,0 +1,22 @@
+#!/bin/bash
+#
+# Copyright 2024 GNOME Foundation, Inc.
+#
+# SPDX-License-Identifier: LGPL-2.1-or-later
+#
+# Original author: Philip Withnall
+
+set -e
+
+# If the test is run under Python (e.g. the first argument to this script is
+# /usr/bin/python3) or if it’s the special xmllint test in GLib, then don’t
+# pass the GTest `-m thorough` argument to it.
+if [[ "$1" == *"python"* ||
+      "$1" == *"xmllint" ]]; then
+  args=()
+else
+  # See the documentation for g_test_init()
+  args=("-m" "thorough")
+fi
+
+exec "$@" "${args[@]}"
\ No newline at end of file
diff --git a/meson.build b/meson.build
index 909ddd26c..e82fdb4ee 100644
--- a/meson.build
+++ b/meson.build
@@ -193,6 +193,13 @@ add_test_setup('unstable_tests',
   #suites: ['flaky', 'unstable']
 )
 
+add_test_setup('thorough',
+  exclude_suites: ['flaky', 'failing', 'performance'],
+  env: common_test_env,
+  timeout_multiplier: 20,
+  exe_wrapper: [find_program('./.gitlab-ci/thorough-test-wrapper.sh', required: true)],
+)
+
 # Allow the tests to be easily run under valgrind using --setup=valgrind
 valgrind = find_program('valgrind', required: false)
 valgrind_suppression_file = files('tools' / 'glib.supp')[0]