Low game performance persists globally. The significant contributions of team and social cohesion to the game performance of team-sport athletes were examined. Using a diagnostic research design, data were collected from 160 respondents selected through complete enumeration. Through multiple linear regression, it was found that both forms of cohesion significantly influence the criterion, fully supporting Social Identity Theory. Future studies may examine additional factors to explain the remaining variance of game performance and consider using qualitative methods to identify new variables. Coaches and school leaders may create programs that strengthen team and social cohesion, with possible reallocation of resources to team cohesion to optimize the performance of team-sport athletes.