This study evaluated the effectiveness of noncontingent reinforcement (NCR) to reduce aggression in autistic children. The study also investigated how NCR may be effectively schedule thinned while still maintaining low levels of aggression. Aggression is a behavior that impacts approximately 53% of autistic individuals and decreases their quality of life (Fitzpatrick et al., 2016; Mazurek et al., 2013). Preference assessments were conducted to ensure appropriate reinforcers were utilized for the functional analyses. Additionally, functional analyses were conducted with participants to assess the behavioral function of their aggression. Following the assessments, baseline levels of aggression were established, and NCR was implemented. NCR resulted in an 80% or more reduction in both participants. Schedule thinning was then initiated. Although differential reinforcement of alternative behavior (DRA) was hypothesized to be necessary to maintain low levels of aggression during schedule thinning, neither participant met the criteria for DRA to be used. This study extended the research by showing the effectiveness of NCR to reduce aggression and maintain the reduction as schedule thinning occurred, making it a more feasible treatment for clinical use. Suggestions for future investigations on the use of NCR in clinical practice, the social validity of NCR, and the impact DRA may have when combined with NCR are discussed.