Walter Traill Dennison (1825 – 3 September 1894) was a farmer, folklorist and antiquarian. A native of the Orkney island of Sanday, in Scotland, he collected local folk tales and other antiquites. Dennison recorded most of the information available about traditional tales told on Orkney, but to an extent “romanticised and systematised” parts of it in the process of transforming the stories into prose. Writing in 2004 and 2010, academics from the University of the Highlands and Islands and University of Glasgow indicated that Traill Dennison had “relied almost exclusively on the peasantry of his native island for the raw materials of his literary work”, and he “provided us with some authentic traditions and that he got these, as he always claimed, directly from the Orkney peasantry”. The Orcadian folklorist and antiquarian Ernest MarwickScottish writer, folklorist and antiquarian particularly noted for his texts on Orkney folklore and history considered that Traill Dennison bridged the gap between the social classes and that he had an “affinity with the common people”.
Traill Dennison published the folk stories, many in the local Orcadian dialect, in 1880 under the title The Orcadian Sketch-Book, published by William Peace & Son, Kirkwall.
Married with one daughter, Traill Dennison died on 3 September 1894 after a short illness.