We proposed a taxonomy of advocate development in the field of developmental disabilities derived from the systematic evaluation of a Partners in Policymaking program. Three developmental stages evolved: beginner, involved, and activist. Self-reports of advocacy actions and outcomes were collected from 3 participants with disabilities and 21 parents before and during training. A follow-up, semi-structured telephone interview was conducted 5 months after training ended. Results indicate significant improvements in the number of actions and outcomes reported by all participants. The activist group had the largest gains in actions and outcomes; they reported twice as many outcomes as did the other participants. The implications of the proposed taxonomy for participants' recruitment in advocacy training programs were discussed.