diff --git a/mesonbuild/mtest.py b/mesonbuild/mtest.py
index 6ccbe5cb2b69..1669e2f23ebd 100644
--- a/mesonbuild/mtest.py
+++ b/mesonbuild/mtest.py
@@ -1187,7 +1187,7 @@ async def parse(self, harness: 'TestHarness', lines: T.AsyncIterator[str]) -> No
                 self.warnings.append('Unknown TAP output lines have been ignored. Please open a feature request to\n'
                                      'implement them, or prefix them with a # if they are not TAP syntax.')
             else:
-                self.warnings.append(str(mlog.red('ERROR')) + ': Unknown TAP output lines for a supported TAP version.\n'
+                self.warnings.append(str(mlog.red('WARNING')) + ': Unknown TAP output lines for a supported TAP version.\n'
                                      'This is probably a bug in the test; if they are not TAP syntax, prefix them with a #')
         if all(t.result is TestResult.SKIP for t in self.results):
             # This includes the case where self.results is empty