Dictionary of Islam is an essential resource in studying Islamic religion written by Thomas Hughes, British missionary noted for his facility with languages and Islamic scholarship. It presents a cyclopedia of the doctrines, rites, ceremonies, and customs, together with the technical and theological terms, of the Mohammedan religion.

Thomas Patrick Hughes (1838-1911) was a British Anglican missionary who served under the auspices of the Church Mission Society in Peshawar for 20 years. Hughes is noted for his facility with languages, Islamic scholarship and contributions to the completion All Saints Memorial Church in Peshawar. His most notable works include A Dictionary of Islam and the official government textbook for learning Pashto.