Mother Teresa MC, known in the Catholic Church as Saint Teresa of Calcutta (26 August 1910 – 5 September 1997), was an Albanian-Indian Roman Catholic nun and missionary. She was born in Skopje (now capital of the Republic of Macedonia), then part of the Kosovo Vilayet in the Ottoman Empire. After having lived in Macedonia for eighteen years, she moved to Ireland and then to India, where she lived for most of her life.

In 1950, Teresa founded the Missionaries of Charity, a Roman Catholic religious congregation, which in 2012 consisted of over 4,500 sisters and was active in 133 countries. They run homes for people dying of HIV/AIDS, leprosy and tuberculosis; soup kitchens; dispensaries and mobile clinics; children's and family counselling programmes; orphanages; and schools. Members must adhere to the vows of chastity, poverty, and obedience, as well as a fourth vow, to give "wholehearted free service to the poorest of the poor".

Teresa was the recipient of numerous honours, including the 1962 Ramon Magsaysay Peace Prize and 1979 Nobel Peace Prize. She was canonised (recognised by the church as a saint) on 4 September 2016, and the anniversary of her death, 5 September, was made her feast day.

A controversial figure both during her life and after her death, Teresa was widely admired by many for her charitable works. She was both praised and criticised for her anti-abortion views. She was criticised for the poor conditions in the houses for the dying she ran. Her authorised biography was written by Indian civil servant Navin Chawla and published in 1992, and there are other books and films about her.