Airbus and Iran Air have finalised a deal for 100 planes worth more than 18 billion dollars (£14.6 billion) at list prices - a contract which could provide a boost for Iran's post-sanctions economy.
Under the terms of the deal, which was initially announced in January, Airbus said deliveries are expected to begin early next year.
The contract includes single-aisle A320 and A330 jets and wide-body A350 XWB planes.
As well as further modernising Iran's aviation fleet, which has been hobbled by years of sanctions, the deal is also a boon to Airbus as Iran's flag carrier had finalised a deal for 80 jetliners from US plane maker Boeing - Airbus' key rival - earlier this month.
In addition to providing the planes, Airbus is to help Iran Air with pilot training, assist with airport operations and air traffic management.
The Boeing agreement was the biggest Iran has struck with an American company since the 1979 revolution and US Embassy takeover. The Boeing planes are scheduled to start arriving in 2018.
The deals were made possible after the US and other world powers agreed last year to lift the sanctions on Iran in exchange for curbs on its nuclear activities.
Iran Air CEO Farhad Parvaresh said of the Airbus deal: "We hope this success signals to the world that the commercial goals of Iran and its counterparts are better achieved with international cooperation and collaboration."
US president-elect Donald Trump and several senior Republicans have criticised the nuclear deal, but it is unclear whether they would scrap it.
Most of Iran's ageing fleet of 250 commercial planes was purchased before 1979, and as of June only 162 were operational, with the rest grounded because of a lack of spare parts.
Iran has said it is looking to buy 400 passenger planes over the next decade.