The All Progressives Congress (APC) is one of the two major contemporary political parties in Nigeria, along with the Peoples Democratic Party (PDP). Founded on 6 February 2013 from a merger of Nigeria's three largest opposition parties, the party came to power following the victory of party candidate Muhammadu Buhari in the 2015 presidential election. This marked the first time in Nigerian history that an opposition party unseated a governing party and power was transferred peacefully.

In 2015, the APC won the majority of seats in the Senate and the House of Representatives, although it fell shy of winning a super-majority to override the ability of PDP to block legislation. During Buhari's first term, waves of defections led the party to lose its federal legislative majorities in 2018, with both Senate President Bukola Saraki and House Speaker Yakubu Dogara among the dozens of lawmakers that defected to the PDP. Nonetheless, Buhari was reelected in the 2019 general election, which also saw the party solidify its majorities in both chambers.

In the 2023 general election, APC candidate Bola Tinubu won the presidential election. He was declared winner by Independent National Electoral Commission (INEC) polling 8,794,726 votes.

Formed in February 2013, the party is the result of a merger of Nigeria's three largest opposition parties – the Action Congress of Nigeria (ACN), the Congress for Progressive Change (CPC), and the All Nigeria Peoples Party (ANPP) along with a breakaway faction of the All Progressives Grand Alliance (APGA) and the new PDP – a faction of then ruling People's Democratic Party. The resolution was signed by Tom Ikimi, who represented the ACN; Senator Annie Okonkwo on behalf of APGA; Ibrahim Shekarau, the Chairman of ANPP's Merger Committee; and Garba Shehu, the Chairman of CPC's Merger Committee.

The party received approval from the nation's Independent National Electoral Commission (INEC) on 31 July 2013 to become a political party and subsequently withdrew the operating licenses of the three parties that merged (the ACN, CPC and ANPP). In March 2013, it was reported that two other associations – African Peoples Congress and All Patriotic Citizens – also applied for INEC registration, adopting APC as an acronym as well, reportedly "a development interpreted to be a move to thwart the successful coalition of the opposition parties, ahead of the 2015 general elections." It was reported in April 2013 that the party was considering changing its name to the All Progressive Congress of Nigeria (APCN) to avoid further complications. However, the party name remained.

In November 2013, five serving Governors from the governing PDP defected to the APC: Rotimi Amaechi of Rivers State, Abdulfatah Ahmed of Kwara State, Rabiu Kwankwaso of Kano State, Murtala Nyako of Adamawa State and Aliyu Wamakko of Sokoto State. It had been previously reported that Governors Mu'azu Babangida Aliyu of Niger State and Sule Lamido of Jigawa State were set to defect from the People's Democratic Party to the APC; however, both ended up remaining with the People's Democratic Party. Amid the governors' defections, nearly 50 federal legislators (including Speaker of the House of Representatives Aminu Tambuwal) joined the party, adding to the 137 legislators in the APC as a result of the prior merger of the smaller opposition parties. These legislative defections initially gave the APC a slim majority of 186 legislators in the Lower House out of a total of 360 legislators; however, subsequent political wrangling and pressure from political factions and interests outside the National Assembly, gave the party only 37 additional legislators thus giving the APC a nominal majority of 172 out of 360 Legislators, as opposed to the PDP's 171 (although some smaller PDP-allied parties held the balance of the other seats). This was further confirmed when the party seated 179 members on 15 January 2015 when the House resumed after a long recess to finally affirm its majority.

Among the party's first electoral tests were a number of off-year gubernatorial elections with the party nominee coming third in Anambra State in 2013 while the next year, the APC incumbent was unseated in Ekiti State but the party's incumbent in Osun State was re-elected. Despite its short history, the party faced infighting in 2014 as several notable members including Okonkwo, Ikimi, and Shekarau resigned from the party and joined the PDP.

Ahead of the elections, the party presidential primary was held on 10 December 2014 with former military dictator Muhammadu Buhari winning by a significant margin. In the federal elections on 28 and 29 March 2015, Buhari emerged victorious over incumbent Goodluck Jonathan by 2.6 million votes—a margin of nine percentage points. The APC expanded its House of Representatives majority to over 210 seats and gained a majority in the Senate with 60 seats. In state elections (mainly on 11 April), 21 governorships were won by the APC while the party also won the majority of state Houses of Assembly.