Purpose: To identify how organizations prepare clinicians to work together to integrate behavioral health and primary care.Methods: Observational cross-case comparison study of 19 U.S. practices, 11 participating in Advancing Care Together, and 8 from the Integration Workforce Study. Practices varied in size, ownership, geographic location, and experience delivering integrated care. Multidisciplinary teams collected data (field notes from direct practice observations, semistructured interviews, and online diaries as reported by practice leaders) and then analyzed the data using a grounded theory approach.Results Behavioral health and primary care integration refers to primary care clinicians (PCCs) and behavioral health clinicians (BHCs) and staff working together with patients to address patients' primary care and behavioral health needs.1 As integrated care becomes a more widely adopted clinical apThis article was externally peer reviewed.