This study aimed to identify factors associated with implementation of cognitive behavioral social skills training (CBSST) on assertive community treatment (ACT) teams in a large public sector behavioral health system. This study used concept mapping (a mixed-method approach) and involved a sample including diverse stakeholder participants including patients, ACT team members, team leaders, organization leaders, and system leaders. We identified 14 distinct issues related to implementing CBSST on ACT teams:(a) CBSST fit with ACT structure,(b) CBSST fit with ACT process,(c) provider perceptions about CBSST,(d) staff pressures/other demands;(e) CBSST and ACT synergy,(f) client characteristics,(g) benefits of CBSST,(h) coordination/interaction among ACT providers,(i) government/regulatory factors,(j) integration of CBSST into ACT,(k) training support,(l) training resources,(m) multilevel agency leadership, and (n) provider characteristics. Each of these dimensions were rated in regard to importance and changeability with the top 5 rated dimensions including effective training support; alignment of leadership across levels of the community-based organizations delivering services; perceived benefits of CBSST, CBSST and ACT synergy; and provider perceptions of CBSST. The most critical issues for CBSST implementation on ACT teams should be addressed in future studies. Implementation strategies that capitalize on enhancing leadership and organizational climate hold promise to address all of these issues.(PsycInfo Database Record (c) 2021 APA, all rights reserved)