Optimizing the actions of volunteers in sport events would be a great help to organize better and more effective events. Therefore, the purpose of this study was to optimize volunteering behavior in sport events. This study was descriptive – analytical which was applied in the field and operational in terms of purpose. The statistical population was experts in the field of volunteering (experienced managers with volunteers and university professors). The sampling method was purposive. In this study, while studying valid certificates and documents in the field of volunteering, 94 criteria were identified in optimizing volunteering behavior in sports events.16 effective criteria were identified in optimizing volunteering behavior and finally, 9 basic criteria were identified by Delphi Method with two repetitions. Then, criteria were determined based on the Best – Worst Method. Regarding that, the model of optimizing volunteering behavior was provided considering time and budget as limitative factors for criteria selection. Finally, 5 scenarios were provided in different budget and time situations and the result of solving the model was acquired by using GAMS software. Thus, sport events managers can participate in the optimization of volunteering behavior and the overall efficiency and effectiveness of the event, considering the scenarios presented in this research.