"I strongly condemn tonight's terrorist attack at a bus stop in central Ankara," Stoltenberg said in a statement, adding "there can be no justification for such heinous acts of violence."
He extend his deepest condolences to those bereaved and wished the wounded a full and rapid recovery.
"All NATO Allies stand in solidarity with Turkey, resolute in our determination to fight terrorism in all its forms," he asserted.
Turkey has been a staunch ally of the 28-nation military bloc and is viewed as a NATO stronghold in the Middle East, protecting its southern borders.
The car bomb blast at a bus stop near Ankara’s central Kizilay square killed 34 people and injured 125, 19 of whom are in serious condition, according to the Turkish health ministry. It comes less than a month after a bomb attack on a military convoy in the capital killed 28 people and wounded dozens more.