The bombers detonated their explosives to avoid being captured during an operation by Turkish security forces in the city which lies close to the Syrian border, AFP quoted state-run news agency Anadolu as reporting.
Local Governor Ali Yerlikaya said three police officers were killed during the incident, with witnesses telling private NTV television they heard gunfire and clashes in the area which is mostly populated by university students.
It was not immediately clear how the police officers died. Another eight people were wounded in the incident, four of them Syrians, the governor said.
Yerlikaya said the raid took place after Turkish authorities gathered intelligence about a possible "suicide bomb attack" by a suspected Daesh "sleeper cell" in Gaziantep.
Since summer 2015, Turkey has suffered a string of attacks in Gaziantep and elsewhere blamed on Daesh terrorists and Kurdish militants.
In August, a deadly suicide bombing at a Kurdish wedding in the city killed 57 people, 34 of them children. The attack was blamed on Daesh terrorists.
In September, the United States warned of the risk of a terror attack in Gaziantep on businesses frequented by Westerners, including the popular coffee chain Starbucks.
At the time, the US Embassy in Ankara warned its citizens that Turkish police were investigating a possible "terror cell" in Gaziantep.
Turkish authorities acknowledge that Daesh terrorists have built up a presence in the southeastern city with the aim of staging attacks, and Sunday's raid was part of a wider crackdown on sleeper cells across the country.