Public teacher compensation is largely determined by fixed salary schedules that were designed to avoid payment inequalities based on demographic characteristics. Yet, recent research shows female teachers earn less than their male peers after controlling for experience, education, and school characteristics. Building on this literature, this paper examines teacher salaries to provide empirical evidence of the extent of gender wage gaps in the teaching profession and the sources of those gaps. Using data from two waves of the National Teacher and Principal Survey, we show that on average male teachers have an advantage of over $700 in base pay and of $1,500 in supplemental compensation, compared to female teachers with similar characteristics and in similar contexts. Additionally, our estimations indicate that male teachers are both more likely to take on extra duties and receive compensation for those activities than female teachers, and the gap increases when schools have a male principal. Finally, an analysis of wage gaps across collective bargaining contexts suggests that wage gaps are positive for both base pay and extra duties, though the magnitudes of each vary across different CBA contexts. Our results provide insight into teacher compensation policies.