Considering the important impact of education on socializing students and preparing the new generation for roles in local, national, and international societies, the educational system is expected to pay special attention to environmental education (EE) in textbooks. The purpose of this study is to investigate the role of EE in social sciences textbooks (SST) in Iranian senior high schools. The research method used was a quantitative content analysis of all SST in senior high schools (3 volumes) during the 2017-2018 academic year. Sentences were used as the analysis unit, and textbook content was divided into four sections based on the cutting operation: text, picture, question, and activity. Shannon entropy method was used for analysing the data. The most significant results indicate that there is no balanced and comprehensive attention given to EE in senior high school SST. The most consideration for EE was found in 11^th grade SST and the highest weight was related to noise pollutants and environmental protection in the Constitution.