This will come as a big surprise to many Nigerians, who had assumed that the Nigerian government had backed down following months of negotiations, says the BBC's Nduka Orjinmo in Abuja.
Nigeria suspended the social media firm last June after it deleted a tweet by President Muhammadu Buhari.
It accused Twitter of siding with secessionists.
Before ending the ban, the Nigerian government insisted that Twitter:
Register in Nigeria
Appoint a designated country representative
Comply with tax obligations in Nigeria