High stress and compromised mental health are well-documented among mothers of children with disabilities, but less is known about the factors that influence their participation and well-being, especially among Chinese mothers. Identifying these factors could lead to strategies to mitigate potential risks to maternal well-being. To explore the relationships among participation in health-promoting activities, perceived stigma, perceived support, and well-being of ethnic Chinese mothers who have children with disabilities. Cross-sectional survey. Community. Ethnic Chinese mothers (N = 261) with children with disabilities of any age residing in Australia, Singapore, or Taiwan. Health Promoting Activities Scale, Personal Wellbeing Index, Warwick-Edinburgh Mental Wellbeing Scale; Kessler Psychological Distress Scale, Parental Perceptions of Public Attitudes Scale, and Multidimensional Scale of Perceived Social Support. Moderate to strong correlations were found between mental well-being and all measures. The frequency of participation in health-promoting activities was a predictor of mental well-being (β = .21, p = .001). Perceived support was the strongest predictor of participation in health-promoting activities (β = .25, p = .005), mental well-being (β = .39, p < .001), and personal well-being (β = .45, p < .001). Perceived stigma predicted psychological distress (β = .32, p < .001) and mental well-being (β = -0.29, p < .001). Perceived support and stigma affected mothers' participation in health-promoting activities and well-being. Therapists can facilitate mothers' engagement in health-promoting activities and develop strategies to address stigma and enhance support. Plain-Language Summary: This research highlights factors that affect the well-being of ethnic Chinese mothers who have children with disabilities and provides cultural insights for occupational therapists who work with Chinese families. The article also encourages pediatric occupational therapists to address the occupational needs and well-being of mothers in parallel with therapy for their children. We discuss occupation-focused strategies, family-centered perspectives, and health promotion approaches in relation to improving the participation and well-being of ethnic Chinese mothers in their cultural context.