Background: Vietnam is a developing country with a health delivery system heavily oriented toward a hospital-based model. The choice of medical specialization training among university students affects future human resource needs, especially practitioners of family medicine (FM). Method: This cross-sectional study was conducted in 2019 in southern Vietnam to identify the percentages of medical specializations chosen from among career categories and determine the factors that influence student choice between FM training and other medical specialization programs. Results: This study involved 1,030 medical students, out of whom 240, 256, 276, and 258 were third-, fourth-, fifth-, and sixth- year students, respectively. Results showed that the students tended to become medical specialists rather than medical practitioners. Those who preferred FM over other disciplines were slightly older (23.8 > 22.95, p = 0.046), belonging to the fifth and sixth years (31.6% and 50% respectively), and more female students than males tended to choose this specialization (63.1% vs 34.2%). Compared with the students who chose other specializations, the FM students were more strongly influenced by friends, placed a stronger emphasis on procedural skills, and sought mastery of few clinical skills. More importantly, the curriculum for medical training and the focus of FM on various medical problems increased interest in FM among the students. Their career choices were relatively affected by internal factors, such as the durations of clinical programs, and external/ environmental determinants, including disease patterns affected by air pollution, seasonal diseases, and societal needs. Conclusion: The findings can help policymakers encourage entry into FM, reorganize current training programs, and emphasize the role and authority. of FM physicians within the Vietnamese health delivery system.