Studies have shown poorer health outcomes for people who identify as sexual and/or gender minority (LGBTQ+) compared to heterosexual peers. Our goal was to establish baseline levels of LGBTQ Ally Identity Measure (AIM) scores: (1) Knowledge and Skills, (2) Openness and Support, and (3) Awareness of Oppression of the LGBTQ+ in surgical trainees, and implement a pilot training in LGBTQ + cultural competency. General surgery residents from a single academic medical center participated in a 2-h educational training developed from the existing Health Care Safe Zone training at our institution. Utilizing the previously validated LGBTQ Ally Identity Measure (AIM), residents responded to 19 items on Likert-type scales from 1 to 5 pretraining and 6 wk posttraining. The residents’ perceptions of the utility of the training were also assessed. Data were analyzed by MANOVA, repeated measures MANOVA, and subsequent univariate analysis. 27 residents responded to the pretraining survey (52%), 22 residents participated in the training, and 10 responded at 6 wk posttraining (19%). The average baseline scores were Knowledge and Skills 19.38 ± 4.64, Openness and Support 25.96 ± 4.31, and Awareness of Oppression 17.15 ± 2.20. Participants who identified as women scored 4.46 (95% CI 0.77-8.15) points higher in Openness and Support compared to males. Of those respondents who completed pretraining and posttraining surveys (n = 10), training had a significant effect on AIM scores with an improvement in Knowledge and Skills (P = 0.024) and Openness and Support (P = 0.042). Residents found the training relevant to surgery patient care (71%), increased their competency in LGBTQ + patient care (86%), and all participants indicated they were better LGBTQ allies following the training. Assessing LGBTQ + allyship in surgical residents, we found that training improved AIM scores over time with significant improvement in the Knowledge and Skills, and Openness and Support scales, suggesting a viable and valuable curriculum focused on sexual and gender identity-related competencies within the graduate medical education for surgical trainees. •Surgical residents lack training opportunities to improve cultural competency in treating LGBTQ patients.•We present a viable and valuable curriculum focused on LGBTQ/sexual and gender identity-related competencies specifically developed to provide training for surgical residents.•LGBTQ cultural competency training improves surgical residents’ ally identity measure scores.•Surgical residents found value in the training as they reported it to be relevant to surgery patient care.