Sweeney Todd is a fictional character who first appeared as the villain of the penny dreadful serial The String of Pearls (1846–1847). The original tale became a feature of 19th-century melodrama and London legend. A barber from Fleet Street, Todd murders his customers with a straight razor and gives their corpses to Mrs. Lovett, his partner in crime, who bakes their flesh into meat pies. The tale has been retold many times since in various media.

Penny dreadfuls were cheap popular serial literature produced during the 19th century in the United Kingdom. The pejorative term is roughly interchangeable with penny horrible, penny awful, and penny blood. The term typically referred to a story published in weekly parts of 8 to 16 pages, each costing one penny. The subject matter of these stories was typically sensational, focusing on the exploits of detectives, criminals, or supernatural entities. First published in the 1830s, penny dreadfuls featured characters such as Sweeney Todd, Dick Turpin, Varney the Vampire, and Spring-heeled Jack.