Occupational burnout among nurses is a major global concern affecting well-being, job performance, and quality of patient care. This hospital-based cross-sectional study assessed the prevalence of burnout and associated factors among 310 nurses at a regional referral hospital in Dar es Salaam, Tanzania. Data were collected using the Maslach Burnout Inventory-Human Services Survey. The prevalence of burnout was 43.5%. High emotional exhaustion, high depersonalization, and low personal accomplishment were reported by 60.3%, 50.9%, and 57.1% of participants, respectively. Burnout was significantly associated with having three or more children (aPR = 2.92; 95% CI: 1.89–4.50), male sex (aPR = 1.33; 95% CI: 1.05–1.68), alcohol use (aPR = 1.38; 95% CI: 1.09–1.75), and presence of chronic illness (aPR = 1.47; 95% CI: 1.11–1.93). Work-related factors including conflict at work (aPR = 1.90; 95% CI: 1.50–2.42) and job dissatisfaction (aPR = 1.60; 95% CI: 1.38–1.87) were also significantly associated with burnout. Burnout among nurses was highly prevalent and was associated with both personal and workplace factors. The findings highlight the need to consider mental health support, workplace conflict, and job satisfaction in strategies aimed at improving nurses' occupational well-being.