The Head of Janus (ger. Der Januskopf) was a 1920 silent film directed by F. W. Murnau. This adaptation of Robert Louis Stevenson's novel The Strange Case of Dr Jekyll and Mr Hyde was one of the earliest to reach film.

Released on September 17, 1920 by the Lipow Co., this is one of Murnau's lost films. The screenplay was written by Hans Janowitz, who collaborated with Carl Mayer in The Cabinet of Dr. Caligari (1919). Whilst the reels themselves do not survive, the scripts and related production notes do - and from these we may piece together some of the more salient points of the plot.

In this uncredited and apparently lost version of Robert Louis Stevenson's "The Strange Case of Dr. Jekyll and Mr. Hyde" the protagonist is Dr. Warren, who indulges his evil nature by periodically turning himself into the depraved Mr. O'Connor. Written by Doug Sederberg