Background Short‐term medical missions (STMMs) refer to the provision of direct pro bono medical services in lower and middle income countries for periods ranging from days to a few weeks by physicians from rich countries. Survey data have provided limited information on demographic and professional profiles of physicians as well as monetary and manpower inputs. Understanding why physicians participate, however, remains incomplete. The study's objective was to elicit physicians' motivations directly. Methods Semi‐structured interviews of physicians identified through snowball recruiting were conducted to explore motivational themes and then analyzed using narrative software employing directed content analysis methodology. Results Twenty physicians from varying backgrounds and specialties were interviewed. Responses identified aspects of the decision to participate and the relative influence of economic, diplomatic, value‐related, and emotive constructs. Conclusion Personality traits may be more influential to participation than demographic, professional, or socioeconomic determinants. Word‐of‐mouth recruitment appears to underlie the increase in STMM activity, facilitated by information technology. Reported key motivators for physician participation in STMMs tend to parallel schools of thought regarding philanthropy and volunteering and include satisfaction from helping in challenging conditions of limited resources, learning experiences, appreciation from patients, sense of renewal, and the legacy effect of teaching.