The Persian Gulf is considered one of the most important regions in the world in terms of geostrategic and geo-economic significance. Thus, maintaining its security is not only vital for neighboring political systems, but it also greatly affects stabilizing or destabilizing the security of the international system. Hence, the Persian Gulf is considered one of the regions that has always been plagued with signs of conflict, contention, and regional wars. Accordingly, this chapter examines the border tensions that have formed in the Persian Gulf region, using a realistic approach. The current study employs a descriptive and analytical research method according to its theoretical nature which is based on library studies, documents, etc. The results of this research show that most countries in this region have border disputes with each other that undoubtedly prevent them from forming cooperative expansion among the countries of the region. But it should be noted that border and territorial disagreement between countries in the Persian Gulf region is not a new phenomenon and it dates back to decades ago. Finally, the challenge of border and territorial dispute in the next two decades makes Iran face border disputes and territorial challenges at different levels and spaces in the Persian Gulf region while providing the context for the formation of other conflicts and disputes and in other words other crises in various geographical regions. It should be noted that these challenges mutually interact and influence each other on wide scale.