Women and children were among the victims of the 15-minute assault Monday in the town of Bilge in southeastern Turkey, Voice of America reported Wednesday.
Witnesses said men, armed with automatic weapons and hand grenades, opened fire on the 200 people attending the wedding.
"The wedding couple put their wedding rings on and as the evening prayers started people started firing through windows and the door," one witness told VOA.
Officials said they thought initially the massacre was part of a conflict between the Turkish state and Kurdish rebels fighting for autonomy. After a preliminary investigation, Turkish Interior Minister Besir Atalay said that scenario was unlikely.
"According to our first inspections, this happened because of a feud within the family," Atalay said. "But our efforts to find out what happened are continuing."
Turkish Prime Minister Recep Tayyip Erdogan condemned the attack.
"To aim a gun against people who are happily celebrating a wedding, to massacre defenseless people including children aged 3, even 1, is evil beyond words, beyond humanity," Erdogan said. "No tradition, no understanding can justify such a killing."