Over the past decades, peer review of teaching has become commonplace at many universities around the world. Though research on the topic is expanding, much of the literature is composed of qualitative studies that offer relevant empirical findings but often have limited foundations in theory. Using a framework synthesis approach, we synthesize the empirical findings of 48 qualitative articles on peer review of teaching into a comprehensive conceptual framework drawing on sociocultural perspectives of learning. We propose the term "collegial faculty development" (CFD) to encompass all practices that support faculty in developing their teaching quality by drawing on the expertise of their colleagues. Our framework conceptualizes the main elements of CFD and shows how different contextual, individual, and relational factors shape the way CFD unfolds. Based on these theoretical considerations, we discuss issues of intersubjectivity, materiality, and temporality as potential avenues for further research.