Conceptualizing and testing factors that contribute to the success of community-academic partnerships are critical to understanding their contributions to the health and well-being of communities. Most measures to date focus on factors that contribute to the development of new partnerships, and only a few have been adequately tested and validated. Methods. The Measurement Approaches to Partnership Success (MAPS) study followed a community-based participatory research (CBPR) approach and a multiphase process that included the construction and pilot testing of a questionnaire, and a national survey to validate the psychometric properties of the questionnaire in long-standing CBPR partnerships (existing [greater than or equal to] six years). All members within partnerships were recruited to complete the survey (55 partnerships with 563 partners). We used confirmatory factor analysis (CFA), Cronbach's alpha statistics, and a pairwise correlations approach to assess discriminant and convergent validity, and assessed internal consistency, and test-retest reliability. Results. All MAPS Questionnaire dimensions demonstrated strong validity and reliability and demonstrated agreement over time. Conclusion. The MAPS Questionnaire includes seven dimensions and 81 items related to the MAPS conceptual model and provides a scientific, in-depth measurement tool that allows long-standing CBPR partnerships to evaluate their work toward achieving health equity.