This article describes a partnership involving a college and its surrounding public high schools in order to offer a model for transforming professional development initiatives into collaborative, reciprocal community engagement opportunities. This ongoing partnership addresses the shared goal of improving the mathematical college readiness of high school students through a three-part program focused on teacher content knowledge. The partnership is based on sustained, open dialogue in which the expertise of all participants, collegiate mathematics professors and high school mathematics teachers, are equally valued and imperative to achieving program outcomes.