At least 17 of the injured were in critical condition following Saturday's attack, Xinhua news agency quoted Health Minister Recep Akdag as saying.
The "terror attack" took place in Sahinbey district of Anatolia region which is about 95 km north of the war-torn Syrian city of Aleppo, Anadolu News Agency reported.
The wedding took place on a street -- a common practice in Turkey, especially during the summer season.
A video footage showed hundreds of people in the darkened street as rescue workers lifted victims into ambulances.
Orhan Akin, Gaziantep bureau chief for the Ihlas News Agency, told CNN Turk that he saw "at least 20 ambulances carrying injured people".
President Recep Tayyip Erdogan, condemned the attack, saying: "Those who cannot overcome Turkey and try to provoke people by abusing ethnic and sectarian sensitiveness will not prevail."
"Our country and nation only have a single message to those who attack us -- you will not succeed!"
Prime Minister Binali Yildirim said Turkey will continue to combat all types of terrorism with determination.
Turkey has experienced significant turmoil in recent months, with the attempted military coup on July 15 and a series of deadly explosions, CNN said.
Past attacks have been carried out by the Islamic State (IS) militant group, which controls northern Syria across the border, and the outlawed Kurdistan Workers Party (PKK).
In the most brazen attack, 44 people were killed on June 28 by suspected IS suicide bombers at Istanbul's Ataturk Airport.
Last March, two suicide bombers killed at least 40 people in Ankara. A Kurdish rebel group claimed responsibility.
On August 10, at least eight people were killed in two explosions in the southeastern towns of Kizitepe and Diyarbakir, CNN added.
No group has yet claimed responsibility for Saturday's attack.
