structural:expansion, structural:summarization
Return to democracy (1999–present)

On 29 May 1999, Abubakar handed over power to the winner of the 1999 presidential election, former military ruler General Olusegun Obasanjo, as President of Nigeria. Obasanjo had been in prison under the dictatorship of Abacha. Obasanjo's inauguration heralded the beginning of the Fourth Nigerian Republic, ending a 39-year period of short-lived democracies, civil war and military dictatorship. Although the elections that brought Obasanjo to power and allowed him to run for a second term in the 2003 presidential elections were condemned as unfree and unfair, Nigeria made significant progress in democratization under Obasanjo.

In the 2007 general elections, Umaru Yar'Adua of the People's Democratic Party came to power. The international community, which had observed the Nigerian elections to promote a free and fair process, condemned these elections as seriously flawed. Yar'Adua died on 5 May 2010, and Vice President Goodluck Jonathan had been sworn in by the Senate three months earlier as acting president to succeed Yar'Adua. Jonathan won the 2011 presidential election; the polls went smoothly and with relatively little violence or electoral fraud. Jonathan's tenure saw an economic recovery that made Nigeria the leading economic power in Africa. The Jonathan administration also saw an increase in unparalleled corruption, with as many as 20 billion US dollars said to have been lost to the Nigerian state through the national oil company. Above all, however, Jonathan's tenure saw the emergence of a wave of terror by the Boko Haram insurgency, such as the Gwoza massacre and Chibok schoolgirls kidnapping in 2014.

Ahead of the general election of 2015, a merger of the biggest opposition parties in Nigeria – the Action Congress of Nigeria, the Congress for Progressive Change, the All Nigeria Peoples Party, a faction of the All Progressives Grand Alliance and the new PDP (a faction of serving governors of the ruling People's Democratic Party) – formed the All Progressives Congress led by current president Bola Ahmed Tinubu. At the time, it was the most expensive election ever to be held on the African continent (being surpassed only by the elections of 2019 and 2023). The new mega-opposition party chose as their candidate for the election former military dictator Muhammadu Buhari. Buhari's campaign in 2015 was popular and built around his image as a staunch anti-corruption fighter—he won the election by over two million votes. Observers generally praised the election as being fair. The election marked the first time an incumbent president had lost re-election in Nigeria. In the 2019 presidential election, Buhari was re-elected.

Four candidates vied for the presidency in the 2023 presidential election. For the first time since the return of democracy, no former military ruler ran for president, marking a strengthening of democracy and faith in the multiparty constitution. The election also saw the rise of metonymic supporters of the new candidates, the Obidient movement of Peter Obi, previously governor of Anambra State, widely appealed to young, urban voters and has his core base in the Southeast; and the Kwankwassiya of Rabiu Kwankwaso, former governor of Kano State in the Northwest.

Bola Tinubu, of the ruling party, won the disputed election with 36.61% of the vote, but both runners-up claimed victory and litigation is ongoing in an election tribunal. Bola Tinubu's inauguration was held on 29 May 2023. Problems with widespread kidnapping in Nigeria continued.