Gustav Diessl (30 December 1899 – 20 March 1948) was an Austrian artist, and film and stage actor.

[citation needed] After the war, Diessl started training as a stage designer but left to pursue a professional career in acting.

[citation needed] That same year he made his film debut, appearing in Im Banne der Kralle, which was produced in Austria and directed by Carl Froelich (G. W. Pabst, who would later direct Diessl in Westfront 1918, made his only appearance as a screen actor in this film).

Over the years, Diessl compiled an extensive filmography, including many romantic comedies, several of which were filmed in war-time Italy.

One of his more notable roles is in the German 1945 propaganda epic Kolberg, which Nazi officials designed to bolster the peoples' morale at a time when a German victory in World War II seemed increasingly hopeless.