The Moral Competence Test (MCT) was designed over 30 years ago to provide a resource for educators interested in conducting cross-cultural studies of moral development and education. Since its origin, it has been translated into at least 30 languages and used in hundreds of studies. However, few studies provide evidence to support the use of the test in the US. The test's designer identified three criteria for evaluating the construct validity of the test and its primary scores: do correlations of stage scores reflect a simplex structure, do ratings follow the theoretical order of stages, does the test differentiate preferences and structures of reasoning. We use these criteria and evidence of criterion and content validity to assess the validity of the MCT. We present results from two US samples (n = 772). Results analyzing the test author's criteria support the semantic validity of the test, however, evidence of criterion validity raise questions about the C-score as a measure of moral competence. After controlling for stage preferences, the C-score was negatively related to democratic attitudes and positively related to dogmatism.