The Contextualized Content Course model implemented by the Boston Science Partnership can be a useful professional development strategy for increasing teacher content knowledge, teacher use of pedagogical approaches encouraged by the district, and student achievement. Teachers who take courses most closely aligned with what they are or will be teaching soon after the courses maximize the retention of the course content. Collaborations between middle and high school teachers and STEM faculty can provide excellent teaching teams for the courses and result in many positive impacts for the middle and high school instructors as well as for the STEM faculty instructors.