Muhammad Hosni El Sayed Mubarak (Arabic: محمد حسني مبارك‎; 4 May 1928 – 25 February 2020) was an Egyptian politician and military officer who served as the fourth president of Egypt from 1981 to 2011.

Before he entered politics, Mubarak was a career officer in the Egyptian Air Force. He served as its commander from 1972 to 1975 and rose to the rank of air chief marshal in 1973. In 1975, he was appointed vice president by President Anwar Sadat and assumed the presidency after his assassination in 1981. Mubarak's presidency lasted almost thirty years, making him Egypt's longest-serving ruler since Muhammad Ali Pasha, who ruled the country for 43 years from 1805 to 1848.

Less than two weeks after the assassination of President Anwar Sadat, Mubarak quickly assumed the presidency in the single-candidate 1981 referendum, and renewed his term through single-candidate referendums in 1987, 1993, and 1999. Under United States pressure, Mubarak held the country's first multi-party election in 2005, which he won. In 1989, he succeeded in reinstating Egypt’s membership in the Arab League, which had been frozen since the Camp David Accords with Israel and returning the Arab League's headquarters back to Cairo. He was known for his supportive stance on the Israeli–Palestinian peace process, in addition to his role in the Gulf War. Despite providing stability and reasons for economic growth, his rule was repressive. The state of emergency, which had not been lifted since the 1967 war, stifled political opposition, the security services became known for their brutality, and corruption became widespread.

Mubarak stepped down during the Egyptian Revolution of 2011 after 18 days of demonstrations. On 11 February 2011, then Vice President Omar Suleiman announced that both Mubarak and Suleiman had resigned and transferred authority to the Supreme Council of the Armed Forces.

On 13 April 2011, a prosecutor ordered Mubarak and his two sons Alaa and Gamal to be detained for 15 days of questioning about allegations of corruption and abuse of power. Mubarak was then ordered to stand trial on charges of negligence for failing to halt the killing of peaceful protesters during the revolution. These trials began on 3 August 2011, making him the first Arab leader to be tried in his own country in an ordinary court of law. On 2 June 2012, an Egyptian court sentenced Mubarak to life imprisonment. After sentencing, he was reported to have suffered a series of health crises. On 13 January 2013, Egypt's Court of Cassation (the nation's high court of appeal) overturned Mubarak's sentence and ordered a retrial. On retrial, Mubarak and his sons were convicted on 9 May 2015 of corruption and given prison sentences. Mubarak was detained in a military hospital while his sons were freed on 12 October 2015 by a Cairo court. Mubarak was acquitted on 2 March 2017 by the Court of Cassation and was released on 24 March 2017.

Mubarak died in 2020, aged 91. He was honoured with a state funeral and buried at a family plot outside Cairo.