"Gadsby" is a 1939 novel by Ernest Vincent Wright. The plot revolves around the dying fictional city of Branton Hills, which is revitalized thanks to the efforts of protagonist John Gadsby and a youth group he organizes.

The novel is written as a lipogram and does not include words that contain the letter "e". Though self-published and little-noticed in its time, the book is a favourite of fans of constrained writing and is a sought-after rarity among some book collectors. Later editions of the book have sometimes carried the alternative subtitle "50,000 Word Novel Without the Letter 'E'". In 1968, the novel entered the public domain in the United States due to failure to renew copyright in the 28th year after publication.