Purpose: Self-care is increasingly advocated for social workers’ well-being, yet its effectiveness remains under-tested in China. This study evaluated a curriculum-embedded self-care course for first-year MSW students. Method: A cluster randomized controlled trial was conducted in six universities. Classroom units were randomized to intervention (eight sessions; n = 116) or control (regular curriculum; n = 96). Stress, anxiety, depression, worry, and mental well-being were measured pre-/post; ANCOVA estimated posttest group differences. Results: Compared with controls, the intervention group showed lower perceived stress and depression and higher mental well-being at posttest (all p < .05). For anxiety and worry, within-group reductions in the intervention group did not translate into significantly greater improvements than in the control group. Discussion: Structured self-care education embedded within social work education can effectively decrease stress and improve mental well-being among MSW students. Integrating self-care into social work education may support the psychological health and sustainability of future practitioners.