diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 7ab52a7f1..4df2394f7 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -58,7 +58,9 @@
 #include "glib-private.h"
 #include "gutilsprivate.h"
 
-#define TAP_SUBTEST_PREFIX "    "  /* a 4-space indented line */
+/* FIXME: Remove '#' prefix when we'll depend on a meson version supporting TAP 14
+ * See https://gitlab.gnome.org/GNOME/glib/-/issues/2885 */
+#define TAP_SUBTEST_PREFIX "#    "  /* a 4-space indented line */
 
 /**
  * SECTION:testing
@@ -1007,7 +1009,7 @@ g_test_log (GTestLogType lbit,
       if (test_tap_log)
         {
           if (!is_subtest)
-            g_print ("TAP version 14\n");
+            g_print ("TAP version 13\n");
           else
             g_print ("# Subtest: %s\n", test_argv0);
 
diff --git a/glib/tests/testing.c b/glib/tests/testing.c
index 658521083..dbbde1733 100644
--- a/glib/tests/testing.c
+++ b/glib/tests/testing.c
@@ -35,8 +35,8 @@
 #include <stdlib.h>
 #include <string.h>
 
-#define TAP_VERSION G_STRINGIFY (14)
-#define TAP_SUBTEST_PREFIX "    "
+#define TAP_VERSION G_STRINGIFY (13)
+#define TAP_SUBTEST_PREFIX "#    "
 
 /* test assertion variants */
 static void