Peter Gregory Obi CON (Igbo: [òbí] ^ⓘ; born 19 July 1961) is a Nigerian politician and businessman who was the Governor of Anambra State from 17 March 2006 until his impeachment on 3 November 2006; he was reinstated on 9 February 2007 and continued his tenure until 2010. He was re-elected for a second term which ended on 7 March 2014. A member of Labour Party since 2022, he was the presidential candidate in the 2023 Nigerian presidential election.

Born in Onitsha, Anambra State, Obi graduated from Christ the King College, Onitsha for his secondary education and University of Nigeria, Nsukka, for his tertiary education. He began his career in banking and later went into politics when he contested for Anambra State Governor in 2003 under the All Progressives Grand Alliance. Chris Ngige was declared the winner but was annulled following a legal ruling challenging the outcome. Obi was later declared the winner and elected candidate, hence becoming the governor on 17 March 2006.

Obi's administration was however interrupted shortly after as he was removed from office by the state assembly 3 November, 2006. The state assembly cited "gross misconduct" on the part of Obi for its action. Obi headed once more to court, as the position of Governor devolved to his deputy, Dame Virginia Etiaba. He was restored to office and resumed as governor 9 February, 2007. Obi was yet to complete his tenure when another election was held to fill the position: the electoral body, INEC, was more interested in keeping to its schedule of elections than consideration of fairness to Obi. This "election" produced Andy Uba of the People's Democratic Party (PDP) as Governor. His swearing in on 29 May, 2007 meant forcible removal of Obi from the governorship seat. Obi was yet once more compelled to seek judicial help. The Supreme Court upheld Obi's position, overturning another illegality to enable Obi serve out his governorship from 14 June, 2007 to 17 March, 2010. Obi successfully ran for re-election and subsequently held the governorship till 17 March, 2014 when he handed over to his successor, Willie Obiano.

Obi sought the Nigerian vice presidential nomination in 2019, along Atiku Abubakar after decamping to Peoples Democratic Party but lost to Muhammadu Buhari. He became a member of the Labour Party in 2022 and was handed the presidential ticket by Patrick Utomi during the primary election of the party. He selected Yusuf Datti Baba-Ahmed as the vice presidential candidate for the 2023 Nigerian presidential election, and their ticket lost to president and vice president, Bola Tinubu and Kashim Shettima. Obi's presidential campaign has been described as populist, especially with firing up a group of supporters called the 'Obidients'.

Obi was born on 19 July 1961, in Onitsha, Anambra State, Nigeria, to a devout Christian family from the town of Agulu. He had his secondary education at Christ the King College, Onitsha, where he obtained his West African Examination Council (WAEC). In 1980, he enrolled in the University of Nigeria in Nsukka, Enugu State, where he studied Philosophy until his graduation in 1984. Obi studied at Lagos Business School, International Institute for Management Development in Switzerland, Harvard Business School, Saïd Business School in England, Cambridge Judge Business School, and Kellogg School of Management.

Obi contested for the Governor of Anambra State under the All Progressives Grand Alliance in 2003, Chris Ngige was declared. Ngige's win in the election was overturned in 2006 by the Court of Appeal, after a ruling at Enugu, which declared Obi the winner of the 2003 election, and he resumed office on 17 March 2006. Obi was impeached on 3 November 2006 by the Anambra State House of Assembly led by the speaker Mike Balonwu. After refusal of participating in the election in April 2007, which would later be won by Andy Uba, Obi challenged the impeachment, which was annulled by the Supreme court of Nigeria. Obi was re-instated on 14 June 2007. On 7 February 2010, Obi won the Anambra State election, and served his second term until 17 March 2014, when he was succeeded by Willie Obiano. After the 2015 General Election, President Goodluck Jonathan appointed Obi as the chairman of the Nigerian Security and Exchange Commission (SEC), and on 12 October 2018, Obi was named as the running mate to Atiku Abubakar under the Peoples Democratic Party's for the presidential election in 2019. The Atiku and Obi ticket finished second behind incumbent Muhammadu Buhari of the APC.

On 24 March 2022, Obi declared his intention to run for President of Nigeria under the party, Peoples Democratic Party (PDP). Afterwards, he pulled out, announcing that he will be running under the Labour Party instead. According to the Nigerian newspaper Peoples Gazette, Obi wrote to the leaders of PDP on 24 May 2022, to resign his membership, as well as reportedly complained of massive bribing of delegates and vote buying during the party's presidential primary, citing the existence of a party clique collaborating against him. Obi's business background and status as a major candidate unaffiliated with either of Nigeria's two main parties has drawn comparisons with Emmanuel Macron's successful 2017 French presidential election.

During the 2023 Presidential election campaign, people under 30 proved to be some of the biggest Obi's supporters, showing their support via social media, protests and street marches. Aisha Yesufu endorsed Obi in her first-ever endorsement of a presidential candidate. Young supporters of Obi's campaign were generally called the "Obidients", which was coined from his name "Obi". In a Business Day opinion article, Chikwurah Isiguzo argued that: