BACKGROUND Professionalism is a core competency of medical education. It impacts one's ability to generate rapport with patients, foster patient satisfaction, and enhance the overall well-being of the medical professional. Unprofessional attitudes among medical students have been associated with higher rates of career dissatisfaction and burnout. A group of faculty and medical students at our institution have developed a series of peer facilitated modules addressing a set of common themes relevant to medical professionalism: professionalism in the clinical setting, professional electronic communication, teamwork and community, and work-life integration. METHODS Student discussions on professionalism were facilitated by senior medical students. Using a 5-point Likert scale, electronic pre- and postsurveys assessed the impact of the workshop on first-year medical students' understanding of various professionalism topics. RESULTS Seventy-seven percent of first-year medical students (n = 131) felt the modules contributed to their learning. Pre- and postsurveys showed significant improvements in understanding of and comfort with the majority of topics discussed. Students felt that their knowledge improved as well. Narrative comments expressed approval of the modules and suggested they addressed unmet needs in the medical curriculum. CONCLUSIONS These modules were successfully incorporated into the first-year medical school curriculum and led to improved student understanding and comfort around these topics. Senior medical student facilitators also found the experience useful in their own career development. Although these modules were designed for medical students, they may also be useful for other professional students (e.g., dental, nursing, etc.) or for interprofessional educational experiences.