The South Caucasus has always been of interest to major powers, and after the collapse of the Soviet Union in 1991, it became a stage for regional and extra-regional power competition. Iran and Russia are among the countries that have focused on the South Caucasus and have sought to expand their influence in this region. This region holds significant strategic importance for both Iran and Russia. One of the important crises in the South Caucasus is the Nagorno-Karabakh conflict, which has had various stages throughout history. The First Nagorno-Karabakh War continued from 1991 to 1994. The Second Nagorno-Karabakh War began on September 27, 2020, and lasted for 44 days. According to the authors, the concept of a "shatter belt" can provide a useful framework for analyzing Iran and Russia's approach to the first and second Nagorno-Karabakh war. In this study, the South Caucasus is considered a shatter belt. In response to the question of "what approach Iran and Russia had towards the first and second Nagorno-Karabakh wars and what factors influenced their approach," the authors propose the hypothesis that "factors such as interest in preserving regional independence and security, mediating in regional conflicts, competing with regional and global powers, internal factors of each country, and the need to realize national interests have influenced Iran and Russia's approach to the first and second Nagorno-Karabakh wars." A descriptive-analytical method has been used to answer this question.