Efforts to strengthen probation programs are often hampered by the lack of a normative theory for probation practice. This study sought to generate a theory of probation practice from the perspective of officers who currently supervise delinquent juveniles on probation. A grounded theory approach was employed with 31 officers who participated in semistructured interviews about their probation practices. Results of the study were synthesized into a comprehensive framework for probation called the participation process model of probation. The participation process model describes change mechanisms that are hypothesized by officers to link their use of specific tactics and strategies with two long-term objectives: risk/need reduction and accountability. Key change mechanisms include youth participation/cooperation, relationship strength, parental support, and motivational processes. The participation process model provides a framework to guide future research and program development. (Published Abstract)