The attackers began spraying bullets at the international terminal entrance before blowing themselves up at around 10:00 pm (1900 GMT) Tuesday, Turkish authorities said.
It is the deadliest of four attacks to rock Turkey’s biggest city this year, with two others blamed on IS and another claimed by a militant Kurdish group.
Though there was no immediate claim of responsibility for Tuesday’s carnage, “the evidence points to Daesh,” Prime Minister Binali Yildirim told journalists at the scene, using another name for the jihadists.
He said the dead included foreigners, but gave no further details.
The attack prompted the suspension of all flights at the airport — one of Europe’s busiest hubs — although Yildirim said traffic would resume at 3:00 am Wednesday (0000 GMT).
Turkish President Recep Tayyip Erdogan called for an international “joint fight” against terror, as Western allies including the United States condemned the “heinous” attack.
Yildirim said the suicide bombers had arrived in a taxi and opened fire on passengers with automatic rifles before blowing themselves up.
Security camera footage widely circulated on social media appeared to capture two of the blasts. In one clip a huge ball of flame erupts at an entrance to the terminal building, scattering terrified passengers.
Tuesday’s attack follows coordinated IS suicide bombings at Brussels airport and a city metro station in March that left 32 people dead.
Erdogan met with his prime minister and military chief after news of the carnage broke.
“We urge the world, especially Western countries, to take a firm stand against terrorism,” Erdogan said in a statement.
“Despite paying a heavy price, Turkey has the power, determination and capacity to continue the fight against terrorism until the end.”
Istanbul, a major tourism hub that is home to some 15 million people, has suffered a series of attacks in recent months, including a bombing in the heart of the tourist district that killed a dozen German visitors and was blamed on IS.
Two months later, three Israelis and an Iranian were killed in a bombing on the city’s main Istiklal shopping street, also blamed on IS.
A blast on the tarmac at Istanbul’s other international airport, Sabiha Gokcen, killed a cleaner in December.
Turkey has been hit by at least five attacks blamed on IS jihadists, including a blast in Ankara in October 2015 that left over 100 dead, though the group has never formally claimed responsibility for an attack in Turkey.
Ankara has meanwhile launched a sustained offensive against the outlawed rebel Kurdistan Workers’ Party (PKK) following the collapse of a ceasefire last year.
Hundreds of members of the Turkish security forces have since been killed in PKK attacks.