The primary goal of (MSP)2 is to strengthen the pipeline of minority students into science and science teaching, and our chief strategy is to focus on inquiry instruction. Inquiry instruction, when done properly, is not only a proven method of improving student learning, it is also inherently suited for reducing the achievement gap by requiring the active participation and interactive engagement of all students. Through a number of different professional development strands for teachers of science, we are demonstrating that each has different effects on teaching practice. Professional development focused on learning science content via inquiry instruction has improved teachers’ content knowledge. Programs focusing more on the process and nature of scientific inquiry have resulted in increased use of inquiry instruction by teachers in their own classrooms and the development of teacher leaders who can help train their peers.