Studies show that physicians and medical trainees who identify as underrepresented in medicine or as women experience higher rates of microaggressions during patient encounters. We designed, implemented, and evaluated an active bystander training workshop focused on mitigating microaggressions using standardized patient (SP) methodology. Internal medicine faculty members and chief residents led the workshop. Participants included 31 PGY 1 categorical and preliminary internal medicine residents. They participated in three case simulations with SPs involving microaggressions from patients toward a member of the health care team. Prior to the case simulations, a brief presentation outlined examples of microaggressions and reviewed the behavioral response framework WAKE (work with who you are, ask questions/make direct statements, involve key people, and employ distraction techniques). After each encounter, residents debriefed with an internal medicine faculty member and discussed questions related to each scenario. All 31 residents participated in the workshop and, before and after the activity, completed a survey that asked them to rank their agreement with statements via a Likert scale. Participants reported statistically significant improvement in recognizing microaggressions (12% reported increase, p = .002), the ability to respond to patients who exhibit microaggressions (23% reported increase, p < .001), and the ability to debrief with team members (20% reported increase, p < .001). SP simulations can be an effective teaching modality for microaggression response strategies during patient encounters. Additional studies are needed to further characterize the workshop's effect on other medical workforce trainees and retention of skills over time.