Duchenne and Becker muscular dystrophy (DBMD) cause significant emotional and care-related burden on caregivers, but no studies have evaluated predictors of positive caregiver outcomes, including disorder-specific psychological adaptation. Using a community-engaged approach focused on supporting mothers in positive aspects of caregiving, this prospective study aims to assess (i) the association between child's baseline functional status and mothers' illness perceptions, resilience, and coping selfefficacy; and (ii) predictors of mothers' psychological adaptation to caring for a child with DBMD. Biological mothers with at least one living child with DBMD completed a baseline survey (n = 205) with 1-year (n = 147) and 2-year (n = 144) follow-up surveys. Worse child's baseline function was associated not only with increased caregiver burden and reduced maternal resilience, but also with perception of positive disease impact on the family. At two follow-ups, increased psychological adaptation to DBMD was predicted by resilience (β = 0.264, P = 0.001) and perceived positive impact (β = 0.310, Po0.001), controlling for mother's age (β = − 0.305, Po0.001) and income (β = − 0.088, P = 0.245). Child's functional status and caregiver burden of DBMD did not predict DBMD-specific adaptation. Though clinicians caring for families with DBMD should anticipate increased caregiver burden as the disorder progresses, interventions focused on caregiver burden are not expected to influence mothers' psychosocial adaptation. Efforts to improve mothers' well-being should focus on fostering mothers' resilience and enhancing perceptions of positive disease impact (benefit finding). Results suggest that psychosocial interventions can highlight strengths and well-being rather than burden and deficit.