The Strange Case of Dr Jekyll and Mr Hyde is the original title of a novel written by the Scottish author Robert Louis Stevenson that was first published in 1886.

It is about a London lawyer named Gabriel John Utterson who investigates strange occurrences between his old friend, Dr. Henry Jekyll and the misanthropic Edward Hyde. The novella's impact is such that it has become a part of the language, with the phrase "Jekyll and Hyde" coming to mean a person who is vastly different in moral character from one situation to the next.

The Strange Case of Dr Jekyll and Mr Hyde was an immediate success and is one of Stevenson's best-selling works.

Stage adaptations began in Boston and London within a year of its publication and it has gone on to inspire scores of major film and stage performances.