Medical students face uncertainty in choosing their future careers, which is influenced by personal and professional factors and can have a direct impact on the healthcare system and society. In this study, we aimed to analyze the magnitude of influence of personal and professional factors on students’ choices of a future specialty, among medical students in Saudi Arabia and other Arab countries. This cross-sectional exploratory study used cluster sampling and collected demographic data, influencing factors, preferred specialty, and engagement level, using a 20-item questionnaire. The study included 1,105 students, of which 60.5% were women. Income was the most influential factor for both sexes (68.5%) and was statistically significant for men (P < 0.0001), with personal experience and type of patients served being more important for women. Many students (42.6%) were undecided about their future specialty. However, general surgery was the most preferred specialty, followed by internal medicine (10.9%) and obstetrics and gynecology (5.5%). Women had a significantly higher mean personal score than men, indicating a preference for surgery (3.07 ± 2.2 vs. 2.78 ± 2.1; P = 0.029). In this study, we found that income significantly influenced medical students’ choices of specialty, with surgery being the most common, and that many students are undecided about their specialty, needing career counseling and mentoring programs.