The purpose was to investigate the mediating role of online social behavior in the relationship between social overload and social identity among sports club managers in South Khorasan Province. The research method was descriptive-correlational. The statistical population of the study was all sports club managers in South Khorasan Province, numbering 250. According to Morgan's table, 150 clubs were selected as the sample. Sampling was done in two stages: cluster sampling in the first stage and random sampling in the second stage. The research instrument included the online social behavior questionnaire of Egers and colleagues (2018), the social overload questionnaire of Meyer and colleagues (2015), and the social identity questionnaire of Safarinejad and colleagues (2010). To ensure the validity of the questionnaires, after their development, the opinions and guidance of expert professors in sports management were used, and their comments were included in the final questionnaire. Subsequently, descriptive statistics (mean, standard deviation) and inferential statistics (Kolmogorov-Smirnov, structural equation modeling) were used to analyze the data using SPSS version 24 and Smart PLS version 3 software at the significance level of α = 0.05. The results of the research showed that social overload has a significant relationship with social identity and online social behavior. Also, online social behavior plays a mediating role in the relationship between social overload and social identity. As a result, holding courses and trainings related to online social behavior, personal information security, and effective digital presence can help sports club managers to perform better in the online space