Mahmoud Ahmadinejad (Persian: , romanized: Mahmd Ahmadned [mhmud(-e) hmdined] (listen)), born Mahmoud Sabbaghian (Persian: , romanized: Mahmoud Sabbghyn, 28 October 1956), is an Iranian conservative politician who served as the sixth president of Iran from 2005 to 2013. He was known for his hardline views and nuclearisation of Iran. He was also the main political leader of the Alliance of Builders of Islamic Iran, a coalition of conservative political groups in the country, and served as mayor of Tehran from 2003 to 2005, reversing many of his predecessor's reforms.

An engineer and teacher from a poor background, ideologically shaped by thinkers such as Navvab Safavi, Jalal Al-e-Ahmad and Ahmad Fardid, Ahmadinejad joined the Office for Strengthening Unity after the Iranian Revolution. Appointed a provincial governor in 1993, he was replaced along with all other provincial governors in 1997 after the election of President Mohammad Khatami and returned to teaching. Tehran's council elected him mayor in 2003. He took a religious hard line, reversing reforms of previous moderate mayors. His 2005 presidential campaign, supported by the Alliance of Builders of Islamic Iran, garnered 62% of the runoff election votes, and he became president on 3 August 2005.During his presidency, Ahmadinejad was a controversial figure in Iran and other countries. He has been criticized domestically for his economic policies and accused of disregard for human rights by organizations in North America and Europe. Outside of Iran, he has been criticized for his hostility towards countries including Israel, Saudi Arabia, the United Kingdom, and the United States and other Western and Arab states. In 2007, Ahmadinejad introduced a gasoline rationing plan to reduce the country's fuel consumption and cut the interest rates that private and public banking facilities could charge. He supports Iran's nuclear program. His election to a second term in 2009 was widely disputed and led to widespread protests domestically and criticism from Western countries.During his second term, Ahmadinejad experienced a power struggle with reformers and other traditionalists in parliament and the Revolutionary Guard and with Supreme Leader Ali Khamenei, over his dismissal of intelligence minister Gholam-Hossein Mohseni-Eje'i and his support for his controversial close adviser, Esfandiar Rahim Mashaei. On 14 March 2012, Ahmadinejad became the first president of the Islamic Republic of Iran to be summoned by the Islamic Consultative Assembly (parliament) to answer questions regarding his presidency. Limited to two terms under the current Iranian constitution, Ahmadinejad supported Mashaei's campaign for president. On 15 June 2013, Hassan Rouhani was elected as Ahmadinejad's successor and assumed office on 3 August 2013.

On 12 April 2017, Ahmadinejad announced that he intended to run for a third term in the 2017 presidential election, against the objections of Supreme Leader Ayatollah Khamenei. His nomination was rejected by the Guardian Council. During the 201718 Iranian protests, Ahmadinejad criticized the current government of Iran. He made a second attempt at registering to run for the 2021 presidential election, and was rejected again by the Guardian Council.

The president of Iran (Persian: رئیس‌جمهور ایران, romanized: Rayis Jomhur-e Irān) is the head of government of the Islamic Republic of Iran. The president is the second highest-ranking official of Iran after the Supreme Leader. The president is required to gain the Supreme Leader's official approval before being sworn in the Parliament and the Supreme Leader has the power to dismiss the elected president if he has either been impeached by Parliament or found guilty of a constitutional violation by the Supreme Court. The president carries out the decrees, and answers to the Supreme Leader, who functions as the country's head of state. Unlike the executive in other countries, the president of Iran does not have full control over the government, which is ultimately under the direct control of the Supreme Leader. Before elections the volunteers must be approved by the guardian council to become a president candidate. Those members of the guardian council are chosen by the supreme leader. The president of Iran is elected for a four-year term by direct vote and is not permitted to run for more than two consecutive terms.

Chapter IX of the Constitution of the Islamic Republic of Iran sets forth the qualifications for presidential candidates. The procedures for presidential election and all other elections in Iran are outlined by the Supreme Leader. The president functions as the executive of the decrees and wishes of the Supreme Leader, including: signing treaties with foreign countries and international organizations; and administering national planning, budget, and state employment affairs. The president also appoints the ministers, subject to the approval of Parliament, as well as to that of the Supreme Leader, who can dismiss or reinstate any of the ministers and vice presidents at any time, regardless of the president or parliament's decision. The Supreme Leader also directly chooses the ministers of Defense, Intelligence, Foreign Affairs, Interior as well as certain other ministries, such as the Science Ministry. Iran's regional policy is directly controlled by the office of the Supreme Leader with the Ministry of Foreign Affairs’ task limited to protocol and ceremonial occasions. All of Iran's ambassadors to Arab countries, for example, are chosen by the Quds Corps, which directly reports to the Supreme Leader.The current long-time Supreme Leader Ali Khamenei, ruling Iran for more than three decades, has issued decrees and made final decisions on economy, education, environment, foreign policy, national planning, and almost everything else in the country. Khamenei has also made final decisions on the degree of transparency in elections in Iran, and has fired and reinstated presidential cabinet appointments.The current president of Iran is Ebrahim Raisi, who assumed office on 3 August 2021, after the 2021 presidential election. He succeeded Hassan Rouhani, who served 8 years in office from 2013 to 2021.