Mairead Maguire (born 27 January 1944), also known as Mairead Corrigan Maguire and formerly as Mairéad Corrigan, is a peace activist from Northern Ireland. She co-founded, with Betty Williams and Ciaran McKeown, the Women for Peace, which later became the Community for Peace People, an organization dedicated to encouraging a peaceful resolution of the Troubles in Northern Ireland. Maguire and Williams were awarded the 1976 Nobel Peace Prize.

Maguire was born into a Roman Catholic community in Belfast, Northern Ireland, the second of eight children – five sisters and two brothers. Her parents were Andrew and Margaret Corrigan. She attended St. Vincent's Primary School, a private Catholic school, until the age of 14, at which time her family could no longer pay for her schooling. After working for a time as a babysitter at a Catholic community centre, she was able to save enough money to enroll in a year of business classes at Miss Gordon's Commercial College, which led her at the age of 16 to a job as an accounting clerk with a local factory. She volunteered regularly with the Legion of Mary, spending her evenings and weekends working with children and visiting inmates at Long Kesh prison. When she was 21 she began working as a secretary for the Guinness brewery, where she remained employed until December 1976.

Maguire told The Progressive in 2013 that her early Catholic heroes included Dorothy Day and the Berrigan brothers.

Maguire became active with the Northern Ireland peace movement after three children of her sister, Anne Maguire, were run over and killed by a car driven by Danny Lennon, a Provisional Irish Republican Army (IRA) member who had been fatally shot by soldiers of the King's Own Royal Border Regiment (KORBR) while trying to escape the troops. Lennon had been released from prison in April 1976 after serving three years for suspected involvement in the IRA. On 10 August, Lennon and accomplice John Chillingworth were transporting an Armalite rifle through Andersonstown, Belfast, when a foot patrol of the KORBR, claiming to have seen a passenger in Lennon's car point a rifle at them fired four shots at the vehicle, instantly killing Lennon and critically wounding Chillingworth. The car Lennon drove went out of control and mounted a pavement on Finaghy Road North, colliding with Anne Maguire and three of her children who were out shopping. Joanne (8) and Andrew (6 weeks) died at the scene; John Maguire (2) succumbed to his injuries at a hospital the following day.

Betty Williams, a resident of Andersonstown who happened to be driving by, witnessed the tragedy and accused the IRA of firing at the British patrol and provoking the incident. In the days that followed she began gathering signatures for a peace petition from Protestants and Catholics and was able to assemble some 200 women to march for peace in Belfast. The march passed near the home of Maguire (then Mairead Corrigan) who joined it. She and Williams thus became "the joint leaders of a virtually spontaneous mass movement."

The next march, to the burial sites of the three Maguire children, brought 10,000 Protestant and Catholic women together. The marchers, including Maguire and Williams, were physically attacked by IRA members. By the end of the month Maguire and Williams had brought 35,000 people onto the streets of Belfast petitioning for peace between the republican and loyalist factions. Initially adopting the name "Women for Peace," the movement changed its name to the gender-neutral "Community of Peace People," or simply "Peace People," when Irish Press correspondent Ciaran McKeown joined. In contrast with the prevailing climate at the time, Maguire was convinced that the most effective way to end the violence was not through violence but through re-education. The organization published a biweekly paper, Peace by Peace, and provided for families of prisoners a bus service to and from Belfast's jails. In 1977, she and Betty Williams received the 1976 Nobel Peace Prize for their efforts. Aged 32 at the time, she was the youngest Nobel Peace Prize laureate until Malala Yousafzai was awarded the Nobel Peace Prize in 2014.

Though Betty Williams resigned from the Peace People in 1980, Maguire has continued her involvement in the organization to this day and has served as the group's honorary president. It has since taken on a more global agenda, addressing an array of social and political issues from around the world.

In January 1980, after a prolonged battle with depression over the loss of her children in the 1976 Finaghy Road incident, Maguire's sister Anne died by suicide. A year and a half later, in September 1981, Mairead married Jackie Maguire, who was her late sister's widower. She has three stepchildren and two children of her own, John Francis (b. 1982) and Luke (b. 1984).