Teachers play a critical role in shaping student success, and the attainment of a graduate degree, particularly a master's degree, has been frequently regarded as an indicator of teacher effectiveness. This report examines state trends in teacher graduate degree attainment with an emphasis on master's degrees, highlighting differences by urbanization, school socioeconomic status, and program major. It also examines rates of major-subject congruence; that is, the alignment between a teacher's graduate degree and their classroom teaching assignment. An overview is then provided of research on the effects of graduate education on student and teacher outcomes. Finally, the report presents several options to improve policies and outcomes related to teacher graduate education, including defining policy goals, improving major-subject congruence, strengthening graduate program quality, broadening effectiveness measures, and enhancing data collection.