The author explores the influence of a professional development program on academics' implementation of active learning in large science courses. Through a qualitative methodology and by employing the transformative learning theory, the author evaluates the influence of science instructors' engagement in dialogue and critical self-reflection on their teaching approaches and practices. Critical reflection is facilitated through watching of teaching videotapes followed by academics' engagement in dialogue about teaching. Findings suggest that providing continuous pedagogical support by fostering engagement in critical self-reflection and dialogue, can lead to transformative learning about teaching. More specifically, participation in this type of professional development leads to the transformation of teaching practices, while teaching approaches remain unchanged. While some obstacles to the transformation of teaching approaches are identified, major outcomes indicate that meaningful professional development can go far beyond learning how to use new teaching strategies and it demonstrates the important role of faculty engagement in critical reflection and dialogue on teaching.