This study aimed to assess the social identity and educational justice relationship in elementary school teachers. This study also investigated organizational citizenship behavior as a moderator in the relationship mentioned above. This applied research had a descriptive, correlational design. The statistical population of the study was comprised of all elementary school teachers in Behshahr in 2018-19 school year (N= 143). Krejcie and Morgan table was used to determine the sample size (N=104) and the sample was drawn via stratified random sampling. The research instruments included Social Identity Questionnaire (SaffariNia & Roshan, 2011), Educational Justice Questionnaire (Golparvar, 2010B), and Organizational Citizenship Behavior Questionnaire (Konovsky & Organ, 1996). Their reliability was calculated to be 0.80, 0.81 and 0.83 respectively by the use of Cronbach’s alpha. The collected data were analyzed by structural equation modeling using the partial least squares method (PLS). The results showed that social identity and organizational citizenship behavior were significantly associated with teachers’ educational justice. In addition, social identity accounted for 48.3% of variance in organizational citizenship behavior and 72.9% variance in educational justice. The results demonstrated that organizational citizenship behavior played a mediating role in the link between social identity and educational justice. Fit indices indicated that the proposed model was a good-fitting one.