US President Donald Trump said on Monday that Washington will impose a 25 percent tariff on all trade with any country that does business with Iran, a sweeping move he declared “effective immediately” that could leave Turkey exposed because it maintains trade and energy ties with its eastern neighbor while also selling billions of dollars of goods to the US.
Trump made the announcement in a post on his Truth Social platform as protests continued in Iran. The White House has not released formal documentation or detailed how the tariff would be implemented, including what is meant by “doing business” with Iran or whether there would be exemptions.
Turkey is a member of the NATO and shares a border with Iran. It has longstanding commercial ties with Tehran, including natural gas imports, even as Iran has faced US sanctions for years.
Iran’s exports to Turkey rose sharply in the most recent period measured. Iran exported $7.3 billion worth of goods to Turkey in the year to October 2025, up from $4.7 billion in 2024, according to figures cited from the Trade Data Monitor. China is Iran’s biggest export partner, buying more than $14 billion of products in the year to October 2025, followed by Iraq at $10.5 billion. The United Arab Emirates and Turkey are also listed among Iran’s largest customers.
The exposure for Ankara comes from the size of Turkey’s trade with the US. The Office of the United States Trade Representative said US goods trade with Turkey totaled about $32.1 billion in 2024, including $16.7 billion in US imports from Turkey and $15.4 billion in US exports to Turkey.
If Trump’s tariff is broadly enforced, it could raise costs across that trade by adding a 25 percent charge at the border on goods traded with the United States by countries deemed to be doing business with Iran.
China, Iran’s biggest trade partner, criticized the move and signaled that it could respond. Trump’s announcement also drew attention in countries that trade with Iran, including Turkey, India, Iraq and the United Arab Emirates.
Turkish officials did not immediately issue a public response to Trump’s tariff announcement.
Energy is a central part of Turkey’s relationship with Iran. Turkey’s state pipeline operator, BOTAŞ, has imported Iranian gas under a long-term agreement that Turkish officials have previously described as running through 2026. In 2018, after the US moved to reimpose sanctions on Iran, Turkey said it would continue buying natural gas from Iran under its contract.
More recently Turkey has been extending and reshaping some of its gas supply arrangements as it seeks to diversify sources while also holding talks related to future supplies, including a contract with Iran.
Trump’s statement did not specify whether the tariff would apply on oil and gas purchases, banking and shipping activity, trade in goods, or a narrower definition. Turkey’s trade with Iran ranges from cross-border commerce to energy flows.
The announcement also raised questions about legal authority and enforcement. The White House had not clarified the legal basis for the tariff. The US Supreme Court is reviewing the legality of some of Trump’s existing tariff measures.
Iran has been under US sanctions for years as Washington has tried to limit its oil revenue and access to the international financial system. In past sanctions campaigns, the US has used “secondary sanctions” to pressure third countries and companies by threatening to cut them off from the US market. Trump’s tariff announcement, if applied broadly, would extend that pressure from targeted entities to whole countries’ trade with the United States.
For Turkey, its US trade is at risk at a time when Ankara relies on export earnings and foreign currency inflows. Any disruption in access to the US market could affect Turkish sectors that ship significant volumes to American buyers.
Trump’s announcement did not include a timeline for how US customs authorities would apply the tariff, whether countries would receive warnings, or whether governments could negotiate waivers. It came as Iran has moved to crush anti-government protests, reportedly killing thousands of people.
Trump did not describe any diplomatic path in his post and did not link the tariff to specific demands beyond the warning itself.