Mother Teresa was the youngest child of Nikola and Drane Bojaxhiu and was originally named 'Agnes Gonxha Bojaxhiu Ans'. Agnes received her first communion at the age of five. From her childhood, she attended prayers and devoted herself in the worship of the Almighty. When Agnes was eight years old, her father died, because of which, the family faced financial crisis. Drane Bojaxhiu, then, assumed the dual role - of being a mother and a father - and helped her children develop a good character. Under the influence and guidance of her mother and a priest, Agnes decided to carry out missionary work.

1910 - 1919 : Agnes Gonxha Bojaxhiu (gonxha meaning "rosebud" or "little flower" in Albanian) was born on 26 August 1910, but she considered 27 August, the day she was baptized, to be her "true birthday". She was born in Skopje, now capital of the Republic of Macedonia, but at the time part of the Ottoman Empire. She was the youngest of the children of Nikollë and Dranafile Bojaxhiu (Bernai). Her father, who was involved in Albanian politics, died in 1919 when she was eight years old. After her father's death, her mother raised her as a Roman Catholic. Her father, Nikollë Bojaxhiu was possibly from Prizren, Kosovo[a] while her mother was possibly from a village near Đakovica, Kosovo.

1928 - 1929 : According to a biography by Joan Graff Clucas, in her early years Agnes was fascinated by stories of the lives of missionaries and their service in Bengal, and by age 12 was convinced that she should commit herself to a religious life. Her final resolution was taken on 15 August 1928, while praying at the shrine of the Black Madonna of Letnice, where she often went on pilgrimage. She left home at age 18 to join the Sisters of Loreto as a missionary. She never again saw her mother or sister. Agnes initially went to the Loreto Abbey in Rathfarnham, Ireland, to learn English, the language the Sisters of Loreto used to teach school children in India. She arrived in India in 1929, and began her novitiate in Darjeeling, near the Himalayan mountains, where she learnt Bengali and taught at the St. Teresa’s School, a schoolhouse close to her convent.

1931 - 1937 : She took her first religious vows as a nun on 24 May 1931. At that time she chose to be named after Thérèse de Lisieux, the patron saint of missionaries, but because one nun in the convent had already chosen that name, Agnes opted for the Spanish spelling Teresa. She took her solemn vows on 14 May 1937, while serving as a teacher at the Loreto convent school in Entally, eastern Calcutta. Teresa served there for almost twenty years and in 1944 was appointed headmistress. Although Teresa enjoyed teaching at the school, she was increasingly disturbed by the poverty surrounding her in Calcutta (Kolkata). The Bengal famine of 1943 brought misery and death to the city; and the outbreak of Hindu/Muslim violence in August 1946 plunged the city into despair and horror.