The tanker caught fire at a town of the southwestern state of Ogun, along the Lagos-Ibadan expressway, according to Florence Okpe, a spokeswoman for the Federal Road Safety Corps in Ogun, Xinhua news agency reported.
A total of 14 bodies were burned beyond recognition, but three others have been identified and taken to a nearby morgue, Okpe told reporters at the scene of the incident.
"The suspected causes of the fatal crash were route violation and dangerous driving, which resulted in a head-on collision and fire outbreak," she said.
The traffic police spokeswoman said although the rescue operation had ended, rescuers who immediately rushed to the scene could not ascertain the total number of people involved.
Deadly road accidents are frequently reported in Nigeria, which are often caused by overloading, bad road conditions, and reckless driving.