In this article we describe a secondary-postsecondary collaborative partnership that addressed the issue of students' frequent failures as they transition from high school to college mathematics courses. Although the partnership did not take place in a professional development school, secondary and postsecondary participants worked together as peers to study pedagogy and content through a professional development approach. Postsecondary participants reported that they valued collegial relationships with secondary teachers and the shared learning and growth they experienced together. The significance of the study for educators and researchers, as well as research funders, is that it emphasizes the value of using collaborative partnerships to work together on studying and aligning instructional approaches, content, and curricula across levels and institutions. This alignment has the potential to strengthen students' abilities to successfully move through the transition points in their education. (Contains 1 table.)