The Sassanid Empire (224-651 AD), after its victory over the Parthians, proceeded to expand the territory of Iran and defend its borders. Taking into account the experience of previous governments, the Sassanids succeeded in creating a centralized and systematic government. In the first half of the 6th century, the eastern territories of Sasanian Iran underwent significant changes. With the collapse of the Heptalian state, the Western Turks emerged as a new power in eastern Iran and, from the 530s, became an influential player in the region's political and military relations. The eastern provinces of the Sasanians, which included regions such as Khorasan, Sistan, Takharistan, and some parts of Central Asia, faced numerous threats and challenges, especially during the reigns of Khosrow I (531-579 CE) and Hormuz IV (579-590 CE). The main purpose of the present study is to examine the foreign policy of the Sasanians with the emerging phenomenon of the Western Turks on the eastern borders and how to mitigate the damage from them. The main question of this research revolves around understanding the relations between Sasanian Iran and the Western Turks and the type of considerations that prevailed between them. Therefore, the present article analyzes Iran's relations with the Western Turks using a historical method and a descriptive-analytical approach, citing primary sources and new data. The research findings show that although the initial alliance with the Western Turks temporarily stabilized security on the eastern borders, the continuation of conflicting interests and competition in Central Asia ultimately paved the way for a new round of border threats that reached their peak in the final decade of the sixth century AD.