Background: The definition of population-specific outcomes is an essential precondition for the implementation of value-based health care. We developed a minimum standard outcome set for overall adult health (OAH) to facilitate the implementation of value-based health care in tracking, comparing, and improving overall health care outcomes of adults across multiple conditions, which would be of particular relevance for primary care and public health populations. Methods: The International Consortium for Health Outcomes Measurement (ICHOM) convened an international panel (patients, clinicians, and topic experts). Following the development of a conceptual framework, a modified Delphi method (supported by public consultations) was implemented to identify, in sequence, the relevant domains, the best instruments for measuring them, the timing of measurement, and the relevant adjustment variables. Findings: Outcomes were identified in relation to overall health status and the domains of physical, mental, and social health. Three instruments covering these domains were identified: PROMIS Scale v1.2—Global Health (10 items), WHO Wellbeing Index (5 items), and the WHO Disability Assessment Schedule 2.0 (12 items). Case-mix variables included a range of sociodemographic and biometric measures. Yearly measurement was proposed for all outcomes and most case-mix variables. Interpretation: The ICHOM OAH Standard Set has been developed through consensus-based methods based on predefined criteria following high standards for the identification and selection of high-quality measures The involvements of a wide range of stakeholders supports the acceptability of the set, which is readily available for use and feasibility testing in clinical settings.