St. John's Diocesan Girls' H.S. School is a girls-only day school located in Kolkata (Calcutta), West Bengal, India. It was established in 1876 by British missionary Angelina Margaret Hoare from Kent, England who devoted her life to the advancement of women's education in British India. It is a Christian school run by the Protestant Church of North India and its primary language of instruction is English. The school's patron saint is Saint John the Baptist. Although previously a college, the school was stripped of its college status by the British Government when freedom-fighter Bina Das, a student of the school, attempted to assassinate the Governor of Bengal, Stanley Jackson.

The Church of North India (CNI) is the dominant united Protestant church in northern India. It was established on 29 November 1970 by bringing together most of the Protestant churches working in northern India. It is a province of the worldwide Anglican Communion and a member of the World Methodist Council and the World Communion of Reformed Churches. The merger, which had been in discussions since 1929, came eventually between the Church of India, Pakistan, Burma and Ceylon (Anglican), the Methodist Church, Disciples of Christ, and some congregations from the United Church of Northern India.