Despite barriers of limited time and lack of formal preparation for teaching, physician-teachers want to do a good job in the classroom. However, without appropriate feedback or self-reflection, physician-teachers have no systematic way to think about their role both in what students learn and in how well they understand important information. With this in mind, the authors developed a model, the Teaching Matrix, designed to encourage clinician-teachers to reflect on their teaching before, during, and after each teaching session. The Matrix helps teachers to address five central questions: Who am I teaching? What am I teaching? How will I teach it? How will I know if the students "got it"? And how will I improve my teaching for the next time? In this paper, the authors describe how the Teaching Matrix may be used as a tool for planning actions, as a "suggestion box" of ideas, advice, and questions, and, most importantly, as a guide to systematic reflection on teaching.