["Psychology in the Schools, EarlyView. ", "\nABSTRACT\nIn‐service training for school staff, generally referred to as professional development (PD), may bolster a school's capacity for implementing school mental health (SMH) services. However, not all PD results in knowledge or behavior change. In one model of PD, Project Extension for Community Healthcare Outcomes (ECHO), participants collaborate with each other and a panel of SMH experts on case consultation and didactics. Although ECHO has shown to have positive effects on school staff's knowledge and self‐efficacy to implement SMH, the effects of ECHO may differ depending on participants' professional background or prior experiences. To test this hypothesis, the current study explored whether role, years of experience, and pre‐test levels of school mental health professional (SMHP) skills predicted key SMH competencies (i.e., clinical self‐efficacy, supervisory self‐efficacy, multicultural skills and knowledge, knowledge of evidence‐based practices, and interprofessional collaboration) at post‐test among SMHPs (N = 47) who participated in ECHO‐based PD. The results indicated that school counselors reported greater clinical self‐efficacy and multicultural skills post‐ECHO compared to other SMHPs, controlling for baseline scores. Knowledge of evidence‐based practices was greater for school psychologists post‐ECHO compared to school counselors, controlling for baseline scores. Years of experience did not significantly predict any outcome measures. The findings suggest that SMHPs may benefit differently from ECHO training based on role. Researchers and educational leaders may wish to consider further developing ECHO to be accessible and relevant to various school‐based professions."]