This research aims to clarify the repercussions of terrorist movements and activities on environmental security and the role played by ISIS in Iraq and Syria because of their negative effects, including long-term damage and pollution, as the areas occupied by ISIS since 2014 have suffered in all their vital aspects, and some of them have not yet been addressed. ISSI destroyed the infrastructure of roads and bridges and disrupted transportation, and oil facilities and electric power stations were exposed to the leakage of chemicals and oil, which caused pollution to the environment, and its impact was greater on the forced displacement of the population in those areas. Add to this its destruction of the culture of environmental and historical value (archaeological and historical sites) after stealing the precious from it. It also played a major role in the biological degradation of logging and poaching that accompanied their terrorist operations. The importance of the research came as a result of the large and qualitative negative effects of terrorism (ISIS) and its repercussions on environmental security and its impact on humans as well, and the study ended with some conclusions and recommendations on the need to eliminate the thought of this organization by strengthening cooperation between countries and relevant organization and developing plans for reconstruction and taking into account environmental sustainability while spreading awareness.