The Blue Castle is a 1926 novel by Canadian author Lucy Maud Montgomery, best known for her novel Anne of Green Gables (1908).

Lucy Maud Montgomery, published as L. M. Montgomery, was a Canadian author best known for a collection of novels, essays, short stories, and poetry beginning in 1908 with Anne of Green Gables. She published 20 novels as well as 530 short stories, 500 poems, and 30 essays. Anne of Green Gables was an immediate success; the title character, orphan Anne Shirley, made Montgomery famous in her lifetime and gave her an international following. Most of the novels were set on Prince Edward Island, and those locations within Canada's smallest province became a literary landmark and popular tourist site – namely Green Gables farm, the genesis of Prince Edward Island National Park. She was made an officer of the Order of the British Empire in 1935.