Given the growing importance of energy in global political and economic developments, its role in the foreign policy of countries has become more prominent. Today, geopolitics of energy and geo-economics play a major role in shaping foreign policy. The main question of this article is: How does energy capacity shape Iran's foreign policy toward Central Asia, particularly Turkmenistan? Based on a theoretical framework grounded in geopolitics of energy and geo-economics and employing a descriptive-analytical method, the main hypothesis of the research is that, given the positions of Iran and Turkmenistan as energy producers and exporters, energy capacity serves as an instrumental function in Iran’s foreign policy. It can contribute to optimizing the energy-driven interests of both countries and reducing Turkmenistan’s geopolitical challenges and Iran’s geo-economic challenges. The findings of the study indicate that although Iran and Turkmenistan, as natural gas producers, may be considered competitors, cooperation based on gas transit and swap agreements can pave the way for expanding bilateral relations and advancing mutual interests. Additionally, routes such as the International North–South Transport Corridor and the connection of Chabahar Port to it will play a significant role in facilitating Turkmen gas exports and consolidating Iran’s position in the regional energy transit chain. However, the operationalization of these capacities faces structural challenges, such as unilateral sanctions and competition among transit routes. Overcoming these challenges requires active bilateral and multilateral diplomacy at the regional level.