Reverend Thomas Kingsmill Abbott (26 March 1829 – 18 December 1913) was an Irish scholar and educator.
Abbott was born in Dublin and was educated at Trinity College. He took his degree in 1851 and was made a fellow of the college in 1854. He obtained an M.A. and a D.Litt. from Trinity, and was ordained a minister in the Church of Ireland.
In 1852 he solved a geometrical problem posed by J. J. Sylvester.
He occupied the chair of moral philosophy (1867–72), of biblical Greek (1875–88), and of Hebrew (1879–1900). In 1887 he was elected librarian in Trinity and, in 1900, completed catalogues of the library's manuscript holdings. He was one of a group of Irish scholars, including J. P. Mahaffy, who made significant contributions to the dissemination and study of the works of Immanuel Kant. His translation of Kant's "Critique of Practical Reason" remained the standard English version of the text well into the 20th century.
In June 1901, he received an honorary doctorate in Divinity from the University of Glasgow.
In 1859 he married Caroline Kingsmill, eldest daughter of the penologist Rev. Joseph Kingsmill.
He died in Killiney in Dublin on 18 December 1913.