Scholars have advocated for the inclusion of metacognition in our understanding of the ethical decision making process and in support of moral learning. An instrument to measure metacognition as a domain-specific capacity related to ethical decision making is not found in the current literature. This research describes the development and validation of the 20-item Moral Metacognition Scale. Psychometric properties of the scale were assessed by exploration and confirmation of the factor structure, and the demonstration of convergent, discriminant, and predictive validity. (...) Moral metacognition, as measured by the MMS, was significantly correlated with ethical awareness and ethical judgment. Limitations of our research, suggestions for future exploration, and practical implications are discussed. (shrink)