diff --git a/scripts/llvm/test-support/run-picolibc-tests.py b/scripts/llvm/test-support/run-picolibc-tests.py
index 8aa3b245..90b88534 100755
--- a/scripts/llvm/test-support/run-picolibc-tests.py
+++ b/scripts/llvm/test-support/run-picolibc-tests.py
@@ -67,7 +67,7 @@ def run_tests(meson_command, source_dir, build_dir, variant):
     )
 
     returncode = subprocess.run(
-        [meson_command, "test"],
+        [meson_command, "test", "-t", "20"],
         cwd=build_dir,
     ).returncode