Parents of children with developmental disabilities (DD) face greater caregiving demands than other parents, which may lead to heightened levels of stress. Characteristics of the child with DD as well as family resources may explain the extensive variability observed in parental adjustment. This study examined trajectories of parenting stress among 108 mother–father dyads parenting a child with DD, from early childhood (age 3) through adolescence (age 15). Using multilevel dyadic analyses, stress was found to increase from early to middle childhood then subsequently decrease through adolescence. Child-related stressors (behavior problems, adaptive behavior) and family resources (social support, positive family climate) in early childhood predicted initial levels and change in stress. Mother–father differences and recommendations for intervention are discussed.