Schools are well positioned to facilitate early identification and intervention for youth with emerging mental health needs through universal mental health screening. Early identification of mental health concerns via screening can improve long-term student development and success, but schools face logistical challenges and lack of pragmatic guidance to develop local screening policies and practices. This study summarizes mental health screening practices tested by six school districts participating in a 15-month learning collaborative. Qualitative analysis of 42 Plan-Do-Study-Act cycles revealed that districts tested quality improvement changes across seven screening practice areas, with all teams conducting at least one test to (1) build a foundation and (2) identify resources, logistics, and administration processes. Quantitative data indicated that the average percentage of total students screened increased from 0% to 22% (range = 270-4850 students screened at follow-up). Together, these results demonstrate how school districts not currently engaged in mental health screening can apply small, specific tests of change to develop a locally-tailored, practical, and scalable process to screen for student mental health concerns. Lessons learned are provided to inform future directions for school-based teams.