Learning collaboratives (LCs) have often been used to improve somatic health care quality in hospitals and other medical settings, and to some extent to improve social services and behavioral health care. This initiative is the first demonstration of a national, systematic LC to advance comprehensive school mental health system quality among school district teams. Twenty-four districts representing urban, rural, and suburban communities in 14 states participated in one of two 15-month LCs. Call attendance (M = 73%) and monthly data submission (M = 98% for PDSA cycles and M = 65% for progress measures) indicated active engagement in and feasibility of this approach. Participants reported that LC methods, particularly data submission, helped them identify, monitor and improve school mental health quality in their district. Qualitative feedback expands quantitative findings by detailing specific benefits and challenges reported by participants and informs recommendations for future research on school mental health LCs. Rapid-cycle tests of improvement allowed teams to pursue challenging and meaningful school mental health quality efforts, including mental health screening in schools, tracking the number of students receiving early intervention (Tier 2) and treatment (Tier 3) services, and monitoring psychosocial and academic improvement for students served.