Armed assailants seized the six students, school vice principal and matron in a dawn raid on their mixed boarding school on October 3.
‘The students and staff of the Engravers College who were abducted have regained their freedom today,’ Samuel Aruwan, Kaduna state internal security and home affairs commissioner said in a short statement, Presstv Reported.
Aruwan did not say how the kidnapped students had been released or if a ransom had been paid.
Kaduna state governor Mallam Nasir El-Rufai told reporters days after the abduction that the kidnappers had made contact demanding ransom payment.
Although the governor declined to give details of those demands, some parents of the hostages said the abductors had demanded 50 million naira ($140,000) for the release of their daughters.
Kidnapping for ransom is common in Nigeria and the school is located near a highway linking Kaduna with Nigeria's capital Abuja that is frequently targeted by criminal gangs.
The area is far to the west of the region notorious for attacks by the Boko Haram militant group.
Boko Haram grabbed headlines around the world in 2014 for the abduction of 276 schoolgirls from the remote northeastern town of Chibok in Borno State.