The explosion, which also left 94 people injured, happened near a wedding hall in the southeastern Turkish province of Gaziantep on Saturday night.
"The Secretary-General hopes that the perpetrators of this act will be quickly identified and brought to justice," said a statement released by Ban's spokesperson.
"He again stresses the need to intensify regional and international efforts to prevent and combat terrorism and violent extremism," it added.
The brutal terror attack was carried out by a teenager, and initial findings showed it was perpetrated by the Islamic State group.