William Crooke CIE FBA (6 August 1848 – 25 October 1923) was a British orientalist and a key figure in the study and documentation of Anglo-Indian folklore. He was born in County Cork, Ireland, and was educated at Erasmus Smith's Tipperary Grammar School and Trinity College, Dublin.

Crooke joined the Indian Civil Service. While an administrator in India, he found abundant material for his researches in the ancient civilizations of the country. He found ample time to write much on the people of India, their religions, beliefs and customs. He was also an accomplished hunter.

Although Crooke was a gifted administrator, his career in the ICS lasted only 25 years because of personality clashes with his superiors. He returned to England and in 1910, he was chosen to be the president of the Anthropological Section of the British Association. In 1911, having been for many years a member of the council of the Folklore Society, he was elected its president. Re-elected as president of the society in the following year, he then became the editor of its journal, Folk-lore, in 1915. He continued in this last position until his death at a nursing home in Cheltenham, Gloucestershire, on 25 October 1923.

Crooke received various honours later in life, including degrees from the universities of Oxford and Dublin and a fellowship of the British Academy.

William Crooke was born on 6 August 1848 in Macroom, County Cork. He was one of three sons of an English family that had been settled in Ireland for many years. His father, Warren, was a doctor. He was educated at Erasmus Smith's Tipperary Grammar School, then won a scholarship to Trinity College, Dublin. He graduated from there with a BA degree.

In 1871, Crooke passed the competitive examination for the Indian Civil Service (ICS). He arrived in India on 2 November and spent his entire 25-year tenure in the North-Western Provinces and Oudh, the area where the Indian Rebellion of 1857 had come close to causing the collapse of British control in India and which had resulted in jurisdiction being taken from the hands of the British East India Company in favour of direct control by the British government. During this time, he held charge as Magistrate and Collector of various districts such as Etah, Saharanpur, Gorakhpur and Mirzapur, and would have held sole power over around 300,000 people with regard to judicial and revenue matters. His near-contemporary, Richard Carnac Temple (1850–1931) described Crooke's work as an "uneventful though strenuous official life" and noted that Crooke had the time to demonstrate his skills in hunting tigers.

In the aftermath of the 1857 revolt, members of the ICS such as Temple believed that if a similar event was to be avoided in the future then it was necessary to obtain a better understanding of their colonial subjects and in particular those from the rural areas. Crooke engaged such a process, working with those subjects in his official capacity and also studying them, although he noted that it was impossible to do both simultaneously because if he asked any general questions during official business then he would be "met with coldness or distrust, or will suddenly find himself unable to make himself unintelligible in the local dialect." These amateur studies led to his 1888 book, A Rural and Agricultural Glossary of the NW Provinces and Oudh, following his contributions to The Indian Antiquary that began in 1882.

Crooke had a burst of activity as a published ethnologist in the field. This began in 1890 when he took over a journal previously edited by Temple, who had moved to Burma. Over the next six years, Crooke's output in the field of ethnography was considerable, comprising the journal, two volumes of Popular Religion and Folklore and the four volumes that make up Tribes and Castes of the North Western Provinces; in addition, he continued to contribute to journals produced by other people.