Background Residents lack confidence in caring for transgender individuals. More exposure and practice throughout training is needed. Objective To explore whether and how prior exposure to transgender health skills during medical school impacted competency with these skills during residency. Methods In 2022, all 101 internal medicine residents at New York University Grossman School of Medicine participated in an objective structured clinical examination (OSCE) station as part of their annual formative assessment where they cared for a standardized patient (SP) who identified as transgender. Three SPs who were members of the transgender community were recruited through online and social media forums. Two resident groups (continuum vs noncontinuum) differed in their prior experiences with transgender OSCEs during medical school. We analyzed SPs' ratings of resident performance using checklist data and SP open-ended feedback to compare performance between groups and resident post-OSCE evaluations to understand residents' perceptions of the educational value of the case. Results Residents with prior experience with transgender SPs (continuum) were more frequently recommended by SPs (88% [21 of 24] vs 70% [54 of 77]) to a family member or friend, were all rated professional (100% [24 of 24] vs 94% [72 of 94]) and scored better in pain information-gathering (92% vs 65%, mean summary score) and gender-affirming care skills (67% vs 52%, mean summary score). Noncontinuum residents lacked experience, missed opportunities to ask about gender identity, and needed work on demonstrating comfort and using proper language. Most residents completing a post-OSCE evaluation (80%, 41 of 51) rated the case as "very valuable." Conclusions Spaced practice and feedback through early exposure to transgender OSCEs were valuable for skill acquisition, giving continuum residents a learning advantage compared to noncontinuum residents.