Health care overuse contributes to unnecessary expenditures and patient exposure to harm. Understanding and addressing this problem requires a comprehensive set of valid metrics. This article describes and critiques the current state of overuse measurement through a review of the published and gray literature, measures clearinghouses and ongoing work by major measure developers. Our review identified 37 fully specified measures and 123 measurement development opportunities. Many services were considered overuse due to the extension of diagnostic or screening services to low-risk populations. There were more diagnostic or therapeutic overuse measures than for screening or monitoring/surveillance. Imaging services is a major focus of current measures, but opportunities exist to expand overuse measurement in medication, laboratory services. Future development of overuse measures would benefit from new empirical research and clinical guidelines focused on identifying indications or populations for which there is likely to be no or low benefit.