Nigeria halted Twitter operations in June, provoking an international outcry over freedom of expression.
The government and Twitter have been in negotiations since over restoring the service based on a set of conditions, including Twitter registering its operations in Nigeria.
"President Muhammadu Buhari... has approved the lifting of the suspension of Twitter operation in Nigeria effective from 12am tonight," the National Information Technology Development Agency (NITDA) said in a statement.
Twitter was accessible in the Nigerian capital of Lagos as of 0600 GMT, an AFP journalist said.
"We are pleased that Twitter has been restored for everyone in Nigeria. Our mission in Nigeria -- and everywhere in the world -- is to serve the public conversation," a Twitter spokesperson told AFP.
"We are deeply committed to Nigeria, where Twitter is used by people for commerce, cultural engagement, and civic participation."
In Africa's largest economy, three quarters of the population of 200 million are younger than 24 -- a generation that is also hyper-connected to social media.
The ban shocked many in Nigeria, where Twitter has had a major role in political discourse, with the hashtags #BringBackOurGirls after Boko Haram kidnapped nearly 300 schoolgirls in 2014.
Young activists turned to Twitter last year to organise the #EndSARS protests against police brutality that eventually grew into the largest demonstrations in Nigeria's modern history before they were repressed.
NITDA director general Kashifu Inuwa Abdullahi said the social media giant had agreed to regulations to restore service.
Those included establishing a legal entity in Nigeria, appointing a country representative and complying with tax obligations.
Abdullahi took part in negotiations with Twitter.
Nigerian officials had criticised Twitter for deleting Buhari's comment while accusing the platform of allowing activities that threatened the country's existence.
That was a reference to social media remarks by separatist agitators from the country's southeast, where a civil war five decades ago killed one million people.
"The immediate and remote cause of the suspension was the unceasing use of the platform by some unscrupulous elements for subversive purposes and criminal activities, propagating fake news, and polarising Nigerians," Abdullahi said.
Twitter deleted a comment when Buhari had referenced Nigeria's civil war, in the context of a warning to those responsible for recent unrest in the country's southeast.
After the ban, officials also referenced then Twitter CEO Jack Dorsey's support for the #EndSARS protests last year in Nigeria against police brutality.
About 40 million people or around 20 percent of Nigeria's population have a Twitter account, according to local researchers, and many used the platform for business.
The United States, European Union and Canada were among those who joined rights groups in condemning the ban as damaging to freedom of expression in Africa's most populous country.