Imposter syndrome (IS) and low self-esteem (SE) are common issues affecting medical students that can impact their well-being and development. This study aimed to assess the prevalence and factors associated with IS and SE among medical students at Jazan University, Saudi Arabia. In this cross-sectional study, 523 medical students in years 2–6 at Jazan University, Saudi Arabia, completed validated questionnaires on IS (Young Imposter Scale) and SE (Rosenberg Self-Esteem Scale). Sociodemographic factors were also collected. Descriptive statistics and logistic regression analyses were used to analyze IS and SE prevalence and correlates. Five hundred twenty-three students with a mean age of 22.09 ± 1.933 participated. The prevalence of low SE and positive IS was 17.6% and 24.3%, respectively. IS and SE had a significant negative correlation (p<0.001). Several sociodemographic factors were associated with increased IS, including 2nd and 4th-year students, forced study choice, and a grade point average (GPA) of 3.0–3.49 (P<0.05). Paternal education beyond high school was associated with lower IS (P<0.05). Logistic regression analyses confirmed that 2nd-year students had a 3.88 times higher odds ratio (OR) (95% confidence interval (CI); 2.19–6.88), and 4th-year students had a 2.37 times higher OR (95% CI; 1.40–4.02) of IS than other years. For SE, advanced academic years, forced study choice, 7+ hours of sleep, and a GPA above 3.5 were associated with higher levels (P<0.05). Negative self-appraisals were associated with lower SE, while positive attitudes were associated with higher SE (P<0.05). Our study reveals that IS and low SE are prevalent among Jazan University, Saudi Arabia, medical students. Therefore, intervention courses that address these issues in medical education at Jazan University, Saudi Arabia, may be necessary to support medical students’ well-being and academic success.