In order to help with the establishment of educational justice, one must first identify the causal factors and their constituents. To this end, a categorized random sample of 924 high school seniors from among all such students in 22 counties in Mazandaran province was selected and given a questionnaire of acceptable validity and reliability. Data analyses show inequality among different counties. Educational/institutional factors play the major role in this inequality, while factors related to the individual and his/her family have the least direct impact. Considering these results, the provincial department of education needs to review and reform many of the programs and improve all aspects of the educational system.