ImportanceWomen account for only 28% of current US medical school deans. Studying the differences between women and men in their preparation to becoming deans might help to explain this discrepancy.ObjectiveTo identify differences in the leadership development experiences between women and men in their ascent to the medical school deanship.Design, Setting, and ParticipantsIn this qualitative study, volunteers from the roster of the Association of American Medical Colleges Council of Deans were solicited and interviewed from June 15 to November 9, 2023. Women deans were recruited first, then men who had been appointed to their deanships at a similar time to their women counterparts were recruited. Deans were interviewed on topics related to number of applications for deanships, prior leadership roles, leadership development, personal factors, and career trajectories. Interviews were coded, and themes were extracted through conventional content analysis.Main Outcome and MeasuresCareer and leadership development experiences were elicited using a semistructured interview guide.ResultsWe interviewed 17 women and 17 men deans, representing 25.8% (34 of 132) of the total population of US medical school deans. Most deans (23 [67.6%]) practiced a medicine-based specialty or subspecialty. No statistically significant differences were found between women and men with regard to years to attain deanship (mean [SD], 2.7 [3.4] vs 3.7 [3.7] years), years as a dean (mean [SD], 5.7 [5.2] vs 6.0 [5.0] years), highest salary during career (mean [SD], $525 769 [$199 936] vs $416 923 [$195 848]), or medical school rankings (mean [SD], 315.5 [394.5] vs 480.5 [448.9]). Their reports indicated substantive gender differences in their paths to becoming a dean. Compared with men, women deans reported having to work harder to advance, while receiving less support and opportunities for leadership positions by their own institutions. Subsequently, women sought leadership development from external programs. Women deans also experienced gender bias when working with search firms.Conclusions and RelevanceThis qualitative study of US medical school deans found that compared with men, women needed to be more proactive, had to participate in external leadership development programs, and had to confront biases during the search process. For rising women leaders, this lack of support had consequences, such as burnout and attrition, potentially affecting the makeup of future generations of medical school deans. Institutional initiatives centering on leadership development of women is needed to mitigate the gender biases and barriers faced by aspiring women leaders.