Improving the education of medical students and physicians can address the disparities in LGBT+ (lesbian, gay, bisexual, transgender, and others) health care. This study explored how teachers used case-based teaching to teach medical students about gender and LGBT+ health care and discussed the implementation and effectiveness of case-based teaching from the perspective of the teachers and students. This study employed the case study method and collected data through semi-structured interviews. This study used two gender courses in clinical psychiatric education as case studies. Two teachers and 19 medical students were recruited as participants. The findings of this study were as follows: (1) effective cases links theory to clinical practice and competency learning; (2) experience sharing by LGBT+ is highly effective; (3) discussions promote the effectiveness of case-based teaching; and (4) the challenges of case-based teaching included time limitations, the multiplexity of the cases, and multilevel learning. This study also found that using narrative cases is a form of narrative pedagogy, which can help students to integrate medicine, gender, and LGBT+ competency education. A successful narrative case–based teaching strategy involves teachers integrating knowledge related to gender, guiding students through the cases to understand the importance of these cases, and reflecting on the medical profession to make improvements. However, teachers face challenges in this approach, such as changes in the school’s teaching culture and a lack of institutional support.