Ultimatum is a 1938 French historical drama film directed by Robert Wiene and Robert Siodmak and starring Dita Parlo, Erich von Stroheim and Abel Jacquin. The film's plot is set in 1914 against the backdrop of the July Crisis between the assassination of Archduke Franz Ferdinand and the beginning of the First World War. It focuses on the relationship between a Serbian officer and his Austrian-born wife and their involvement in espionage between the countries.

It was the final film of Wiene, who had been a leading director of German cinema particularly noted for his work on expressionist films during the silent era. He died shortly before the film's completion, and it was finished by Siodmak.