The focus of this diploma is the legal framework of the United Nations and it's organs in the fight against terrorism. This international organization brought the various relevant documents of terrorism, with the accent on conventions, resolutions and other activities of the United Nations. The beggining of this paper is dedicated to the most famous terrorist organizations that cause a threat to international peace and security. Through the work according to the general problem of the lack of definitions of terrorism, use of the right to self-defense under the UN Charter, the issue of equalization of aggression and terrorist acts. The third chapter touches on the sectoral conventions and protocols and several major resolutions adopted by the United Nations Security Council. The fourth chapter describes other activities of the UN in the fight against terrorism, with the accent on the latest report of the Secretary-General Ban Ki-Moon on the currently most dangerous terrorist organization ISIL. The fifth chapter is dedicated to the draft "Comprehensive convention against international terrorism", which in the practice of the Member States is completely ignored. The last two chapters are conclusion and a list of references. Also, with this paper are tables with resolution in the period from 1989. to 2016.