Sir Thomas Walker Arnold (19 April 1864 – 9 June 1930) was a British orientalist and historian of Islamic art. He taught at Muhammadan Anglo-Oriental College (MAO College), later Aligarh Muslim University, and Government College University, Lahore.
Arnold was a friend of Sir Syed Ahmed Khan, who influenced him to write the famous book The Preaching of Islam, and of Shibli Nomani, with whom he taught at Aligarh. He taught Syed Sulaiman Nadvi and the poet-philosopher Muhammad Iqbal. He was the first English editor for the first edition of The Encyclopaedia of Islam.
Thomas Walker Arnold was born in Devonport, Plymouth on 19 April 1864, and educated at the City of London School and Magdalene College, Cambridge. From 1888, he worked as a teacher at the MAO College, Aligarh.
In 1898, he accepted a post as Professor of Philosophy at the Government College, Lahore and later became Dean of the Oriental Faculty at Punjab University.
From 1904 to 1909, he was on the staff of the India Office as Assistant Librarian. In 1909, he was appointed Educational Adviser to Indian students in Britain. From 1917 to 1920, he acted as Adviser to the Secretary of State for India. He was Professor of Arabic and Islamic Studies at the School of Oriental Studies, University of London, from 1921 to 1930.
Arnold died on 9 June 1930 at Edmonton, Middlesex.
In 1892, Arnold married Celia Mary, a daughter of G. Hickson, and they had one daughter. His wife was a niece of Theodore Beck.