Despite that signing the agreement on Iran’s nuclear program between Iran and the G-5 countries +1 on the fourteenth of July 2015 was expected, as there were many indications especially from the United States to ensure the signing of that agreement, it has sparked a lot of controversy not because of its content but given its timing and the GCC states views towards it. It is too simplistic to look at the agreement only from the perspective of the parties involved, hence it should be viewed in the context of the regional and international environment. The agreement came after several years of negotiations between the two sides, which were was marked by instances of push and pull between them, which reached its extent when the United States tried to refer the Iranian nuclear issue to the Security Council. However, the US was stopped by the Russian veto power. The agreement has a specific timeframe, and therefore did not end Iran’s nuclear ambitions and the possibilty of developing nuclear power for non-peaceful purposes. The agreement might only postpone the development of nuclear weapons by Iran. This raises the fears of the GCC states which suffer from an imbalance in the traditional balance of power with Iran. This is important since Iran establishes it relations with the GCC countries on the basis of balance of power rather than a balance of interests. In light of the many contentious issues between Iran and some GCC countries, the Iranian policy towards the GCC countries and towards regional security issues in general has not seen positive changes in the wake of the signing of the nuclear deal. On the contrary, tensions in the Saudi-Iranian relations aroused in January 2016. The above raises four key questions: First: Why is the nuclear deal considered an important development in the context of the Gulf regional security? Second: Has the nuclear deal ended Iran’s nuclear ambitions, or has it only postponed them? Third: How does the nuclear deal affect Iran’s policies towards the GCC countries and how does it affect regional security? Fourth: What are the GCC options regarding the nuclear deal and regarding Iran’s regional policies?