Cost-inclusive research (CIR) uses observations, interviews, self-reports, and archival records to collect data on the types, amounts, and monetary values of resources that make health psychology interventions (HPIs) possible in healthcare and community settings. These resources include time of practitioners, patients, administrators, space in clinics and hospitals, computer hardware, software, telecommunications, and transportation. CIR adopts a societal perspective by including patient resources such as time spent participating in HPIs, income foregone for participation, travel time and transportation to and from HPI sites, patients’ information devices, and child- and eldercare necessitated by HPI participation. This comprehensive approach to HPIs also distinguishes between costs and outcomes of delivery systems, and of techniques used in HPIs. CIR can help justify funding of HPIs by including not only problem-specific outcomes (effectiveness), but also monetary outcomes (benefits) of HPIs, including changes in patient use of services for health and education, patient criminal justice involvement, financial assistance to patients, and changes in patient income. By measuring the types and amounts of resources consumed in specific activities of HPIs, and monetary and nonmonetary outcomes of HPIs, we can better understand, budget for, and disseminate interventions that work and are accessible by most people who need them. Combining effectiveness findings with data on costs and benefits can build a more complete evidence base for optimizing impacts of health psychology, including empirically selected stepwise interventions to deliver the best interventions in health psychology to the most patients for the least amount of necessary societal and healthcare resources.