The study examined burnout in 328 medical students at Universiti Kebangsaan Malaysia using structured questionnaires, including the Copenhagen Burnout Inventory, assessment of mentorship, motivation and professional values. The prevalence was high: personal burnout in 60.4%, job burnout in 47.3%, and client-related burnout in 32.0%. Mentor accessibility in lecturer mentoring was associated with lower job burnout (p < 0.001, OR = 0.62, 95% CI = 0.47–0.82). In peer mentoring, personal attributes reduced personal burnout (p < 0.001, OR = 0.41, 95% CI = 0.25–0.66) and job burnout (p = 0.013, OR = 0.70, 95% CI = 0.52–0.93). Persistence in motivation was associated with lower job burnout (p < 0.001, OR = 0.85, 95% CI = 0.80–0.92) and client-related burnout (p < 0.001, OR = 0.82, 95% CI = 0.77–0.87). Professional service values reduced client-related burnout (p = 0.009). The authors recommend interventions aimed at improving lecturer and peer mentoring, strengthening motivation and professional values during studies.