This article synthesizes the literature on self-determination across the lifespan with a focus on identifying gaps that exist between theory, research, and evidence-based practices. Using a life-stages approach, it first examines issues across life phases, and then examines cross-cutting topics (employment, abuse and neglect, and health) that are relevant during several age ranges. A lifespan approach to self-determination takes into account both the developmental stage and the social ecological aspect. While its expression for individuals with developmental disabilities can begin at the earliest stages, in general, level of self-determination increases throughout adolescence and early adulthood. The expression of self-determination is also shaped by opportunities in family, school, vocational, and residential environments. In addition, such practices and policies such as consumer-direction in supports and training interventions that teach elements of goal planning and choice-making and self-regulation contribute to greater self-determination of individuals with developmental disabilities.