BACKGROUND: Under the Workforce Innovation and Opportunity Act of 2014 (WIOA), vocational rehabilitation (VR) agencies are required to evaluate their students’ need for pre-employment transition services and use this information to inform their goals, priorities and strategies. OBJECTIVE: This manuscript presents the development and field testing of the Transition Self-Assessment Tool (TSAT), a web-based instrument designed to support VR agencies’ evaluation and strategic planning initiatives by measuring the availability, accessibility, and coordination of school-based transition services. METHOD: Our methods describe the TSAT development procedures and the methods of conducting a TSAT field test. RESULTS: Findings suggest high schools offer a broad array of career-related services for their students. However, not all potentially eligible students with disabilities have access to those services and when these services are provided, they are frequently delivered without coordination with VR. Additionally, data show more services are available, accessed, and coordinated in high schools participating in a statewide transition program. CONCLUSION: Results from the TSAT field test suggest it is feasible to conduct a statewide needs assessment of school-based transition services using this instrument. Furthermore, the findings from the TSAT align with prior knowledge about school-based transition services, and can be used to inform a state’s goals, priorities and strategies.