“People who live in glass houses should not throw stones.”
- Turkish Foreign Minister Hakan Fidan, interview with Al Jazeera Arabic on 26 February 2025
Three months later, this strong warning looks less like a threat and more like a prediction. A decade ago, Iran was the region’s shadow puppeteer, proudly proclaiming its control over four Arab capitals. However, its projection of power through proxies backfired. Ironically, this helped facilitate the surprise offensive of Hayat Tahrir al-Sham (HTS) in Syria, a former al-Qaeda affiliate, backed by Tehran’s regional rival, Türkiye. Moreover, its archenemy, Israel, has steadily weakened Iran and Hezbollah’s military capabilities in both Lebanon and Syria, especially following Iran-backed Hamas’ deadly cross-border attack on October 7, 2023, which indirectly enabled HTS’ takeover of Syria, the indispensable “jewel in the crown” of Iran’s regional network.[Metin Kaydırma Sonu]Türkiye and Iran have been regional rivals for decades, with Syria as a key battleground. Assad’s downfall in December 2024 was a serious strategic blow to Iran and resulted in a power vacuum that Ankara is increasingly filling. Today, Türkiye is capitalizing on Iran’s declining regional influence and is building what Iran could not: regional partnerships and not just proxies. While the competition for dominance between the two neighboring adversaries is intensifying in Syria and Iraq, it is also extending beyond the Middle East.
Historical background
Although the Ottoman and Safavid empires fought several wars, modern-day Türkiye and Iran -widely viewed as the successors of those imperial legacies- often emphasize the enduring significance of the 1639 Treaty of Kasr-ı Shirin (Zuhab) as the foundation of their centuries-old friendship with one of the Middle East’s most stable frontiers. Despite their deep-rooted geopolitical rivalry, both countries frequently invoke this historical reference to frame their bilateral relations as peaceful and stable.
Sharing a long border, these two non-Arab regional powers have developed a relationship best described as a “cooperative rivalry.” The Arab Spring has intensified their political and ideological competition for influence, with both countries seeking to capitalize on the emerging new regional order. Despite often competing for influence and supporting opposing sides in conflicts, they continued to pursue ways to strengthen their economic ties and invest in their partnerships through mediation efforts, such as the Astana Process, which also involved Russia. Both countries managed complex challenges without major friction despite their competing interests. However, this delicate balance suffered a significant crack in early 2025 with a diplomatic crisis that became a clear manifestation of deeper strategic rivalry between Türkiye and Iran, based on shifts in regional influence, ideological divergences, and competing geopolitical ambitions.
The Kurdish issue
This latest dispute follows Iranian criticism of Türkiye’s Syria policy following the call by jailed Kurdistan Workers’ Party (PKK) leader Abdullah Öcalan, who urged his group to disarm. In response, Turkish Foreign Minister Hakan Fidan warned Iran against meddling in others’ internal affairs, suggesting such actions could backfire, in a rare and veiled threat. Tensions were already high due to reports signaling Iran’s military support to the PKK, a group designated as a terrorist organization by Türkiye, Iran, and the United States.
Türkiye now sees a golden opportunity to resolve this decades-old conflict, given its relatively good relations with Baghdad and Damascus, as well as its strong regional position. Ankara believes the PKK has no other alternative but to abandon the fight. However, it remains highly sensitive to Iran’s potential support for the PKK and its offshoots in Iran, Syria, or Iraq. Tehran, on the other hand, is concerned about the growing coordination between Türkiye and the United States to reduce Iran’s influence in Syria and Iraq.
Post-Assad Syria: A game changer
With the fall of the Assad regime, Türkiye and Israel have emerged as key power brokers in Syria, effectively taking up the vacuum created by the waning influence of Russia and Iran. The United States initially adopted a wait-and-see approach, but this stance shifted in May 2025 with a landmark meeting between U.S. President Donald Trump and Syria’s interim President Ahmed Al-Sharaa in Saudi Arabia.
This meeting was central as it marked the tentative recognition of the new political order in Syria. Trump later announced the lifting of U.S. sanctions on Syria, crediting Türkiye and Saudi Arabia. The EU followed suit after a meeting of foreign ministers in Brussels on May 20. This shift marks a victory for Al-Sharaa and also a win for Türkiye. This development underscores Iran’s marginalization after years of costly interventions to keep Assad in power. More broadly, it illustrates Ankara as a middle power that continues to punch above its weight in regional and international affairs. Türkiye’s influence extends from Iraq and the South Caucasus to Central Asia and Africa, literally replacing Iran’s eroding power.
Connectivity and trade corridors
In the South Caucasus, Iran and Türkiye are increasingly at odds, competing for regional supremacy in a territory that has emerged as a geopolitical fault line following the 2020 Nagorno-Karabakh War. Türkiye’s strong relations with Azerbaijan, which is often described as “one nation, two states,” and its influence in determining the results of the Second Karabakh War have notably shifted the balance of power, benefiting Türkiye, while marginalizing Iran in the process. Tehran perceives the expanding partnership among Türkiye, Azerbaijan, and Israel, particularly in the realms of defense, energy, and connectivity projects, as a threat to its strategic depth and regional influence, particularly as it faces U.S. sanctions that further alienate Iran from international markets.
Türkiye positions itself as a unifying force among Turkic nations, enhancing its involvement in the South Caucasus and Central Asia. In contrast, lacking a clear pathway to challenge Türkiye’s increasing hegemony in the region, Iran has resorted to defensive measures such as strengthening its relationship with Armenia and conducting military drills near the Azerbaijani border. Additionally, Tehran perceives Ankara’s determination for the Zangezur Corridor as an existential threat, severing its connection to Armenia and reducing its access to northern routes. Iran sees this initiative as “Türkiye’s highway to Turan” and a Pan-Turkism project supported by NATO.[Metin Kaydırma Sonu]Meanwhile, the Middle Corridor (Trans-Caspian International Transport Route) has become strategically vital as a safer and preferred route, particularly since Russia’s invasion of Ukraine in 2022 and the increased Houthi attacks on vessels in the Red Sea. Connecting Europe and China via Central Asia and the South Caucasus, the Middle Corridor bypasses Russia and Iran while reaffirming Türkiye’s role as a pivotal hub for global trade. Iran is largely excluded from this initiative due to its poor infrastructure, lack of investments, and international sanctions.
Moreover, Iran’s hope to position itself as a vital transit route within the Middle Corridor via Iraq, Syria, and the Mediterranean Sea, has been dashed by the fall of Assad. Türkiye’s growing role in Northern Syria diminishes the prospects of Iran’s relevance in east-west trade routes. Tehran is attempting new ways to connect itself to connectivity projects via the Turkmenistan-Uzbekistan route or through Afghanistan, aiming to secure a stronger foothold within regional trade routes.
Strategic implications of the Türkiye-Iran rivalry
Wherever Iran looks, it now sees Türkiye; expanding its diplomatic, economic, and military presence across Eurasia, the Middle East, and Africa with its involvement in the Russia-Ukraine peace negotiations, the Ethiopia-Somalia reconciliation, its growing influence in Libya, and Taliban-controlled Afghanistan, its expanding economic, military, and security presence in the Gulf and Africa’s Sahel.
The fall of the Assad regime in Syria dismantled Iran’s politico-military infrastructure, setting back its regional ambitions. In response, the Red Sea has emerged as the most active front in Iran’s sphere of influence, where it employs asymmetric maritime tactics and proxy warfare through the Houthis to expand its presence and deter Western influence. This strategy poses a significant challenge to global maritime security and shifts regional power dynamics in favor of Iran and its allies.
The intensifying rivalry between Türkiye and Iran has been reshaping regional dynamics. Weakened by international sanctions, diplomatic isolation, pressure on its nuclear program, domestic disturbances, economic problems, and setbacks in Syria and its proxy network, Iran has been increasingly sidelined in diplomatic processes and key trade routes. In contrast, Türkiye is expanding its influence through conflict mediation, humanitarian aid, infrastructure projects, and security cooperation, becoming a central player across Eurasia, the Middle East, and Africa.
For the European Union and the United States, this shift presents risks and opportunities. Ankara’s proactive multilateral diplomatic efforts possess the potential to mitigate Iran’s regional influence and address power vacuums. However, Türkiye’s assertive and autonomous foreign policy approach demands careful engagement. Meanwhile, Iran’s isolation and fading influence may push it further toward Russia and China, thereby strengthening a competing geopolitical bloc. Comprehending the nature and consequences of this rivalry is crucial for any enduring strategy in the region.
