George Oliver Onions (13 November 1873 – 9 April 1961), who published under the name Oliver Onions, was an English writer of short stories and novels. He wrote in various genres, but is perhaps best remembered for his ghost stories, notably the collection Widdershins and the widely anthologized novella "The Beckoning Fair One". He was married to the novelist Berta Ruck.

George Oliver Onions was born on 13 November 1873 in Bradford, Yorkshire, England, to George Frederick Onions, a bank cashier (born 1847, London, England) and Emily Alice Fearnley (born 1850, Scholes, Yorkshire, England). He studied art for three years in London at the National Arts Training Schools (now the Royal College of Art). In the book Twentieth Century Authors, Onions described his interests as motoring and science; he was also an amateur boxer as a young man.

In 1909, Onions married the writer Berta Ruck (1878–1978) and they had two sons: Arthur (born 1912) and William (born 1913). In 1918, he legally changed his name to George Oliver, but continued to publish under the name Oliver Onions.

He died on 9 April 1961 in Aberystwyth, Wales.

Originally trained as a commercial artist, he worked as a designer of posters and books and as a magazine illustrator during the Boer War. Encouraged by the American writer Gelett Burgess, Onions began writing fiction. The first editions of his novels were published with dust jackets bearing full-colour illustrations painted by Onions himself.

Poor Man's Tapestry (1946) and its prequel, Arras of Youth (1949) are about the adventures of a juggler, Robert Gandelyn, in the 14th century. The Story of Ragged Robyn (1945) focuses on the adventures of the titular stonemason at the end of the 17th century, inspired by the Yorkshire legend of Peg Fyfe. Onions wrote two detective novels: A Case in Camera and In Accordance with the Evidence. Two of his works are science fiction novels: New Moon (1918) about a utopian Britain, and The Tower of Oblivion (1921), featuring a middle-aged man who recedes back to his youth. A Certain Man (1931), about a magical suit of clothes, and A Shilling to Spend (1965), about a self-perpetuating coin, are fantasy novels.

Onions wrote several collections focusing on ghost stories and other weird fiction. The best known of these collections is Widdershins (1911). It includes the novella "The Beckoning Fair One", widely placed among the best in the genre of horror fiction, especially psychological horror. On the surface, it is a conventional haunted house story: an unsuccessful writer moves into rooms in an otherwise empty house, in the hope that isolation will help his failing creativity. His sensitivity and imagination are enhanced by his seclusion, but his art, his only friend and his sanity are all destroyed in the process. The story can be read as narrating the gradual possession of the protagonist by a mysterious and possessive feminine spirit, or as a realistic description of a psychotic outbreak culminating in catatonia and murder, told from the psychotic subject's point of view.

A theme that "The Beckoning Fair One" shares with others of Onions's stories is a connection between creativity and insanity; here the artist is in danger of withdrawing from the world altogether and losing himself in his creation. Another noted story from Widdershins is "Rooum", about an engineer pursued by a mysterious entity. Other ghost stories such as "The Cigarette Case", "The Rosewood Door" and "The Rope in the Rafters" involve time and identity shifts.