Background <p>Scholars have previously demonstrated a link between backgrounds in the social sciences and humanities and humanistic qualities, yet the literature exploring the relationship between undergraduate college major and specialty choice is equivocal, in part because previous studies have rarely used nationally representative datasets. Further, there are many potential mediating factors that may influence this relationship.</p> Methods <p>This cross-sectional study aimed to investigate whether undergraduate college major relates to future specialty and explored potential mediating factors in this relationship. In particular, the authors investigated the relationship between social science and humanities college major and choice of either primary care or non-procedural specialties. A regression modeling approach was used with a U.S.-based national dataset that included 49,214 individuals who participated in the 2018–2020 Association of American Medical Colleges (AAMC) Graduation Questionnaires (GQ). Study participants represent about 82% of the 59,887 graduates from U.S. allopathic medical schools between 2018 and 2020.</p> Results <p>Overall, medical students who majored in the humanities and social sciences were more likely than their science, technology, engineering, and mathematics (STEM) major peers to choose primary care specialties and to choose non-procedural specialties. These relationships were consistent even when considering other social identity and performance factors. Additionally, medical students who took “patient-focused” electives were more likely than those who did not to choose primary care and non-procedural specialties.</p> Conclusions <p>A promising approach to increase the number of future primary care physicians in the US may be to recruit more social science and humanities majors.</p>