This study investigates the role of an inquiry professional development institute in empowering middle school mathematics and science teachers to develop as teacher leaders. Teachers and coaches jointly attended content sessions and participated in practice teaching sessions with students. The coaches led reflection sessions following the practice teaching sessions. Using stages 1 and 2 of the Principles and Indicators for Mathematics Education Leaders Leadership Framework modified to include science as a data analysis tool, data from 16 teachers informed the study. Results showed that after teachers completed the professional development, they grew as teacher leaders, with 11 and 14 teachers reaching Stage 2 Leadership in each leadership area, respectively.