Tim Frazer and the Mysterious Mister X (German: Tim Frazer jagt den geheimnisvollen Mister X) is a 1964 Austrian-Belgian crime thriller film directed by Ernst Hofbauer and starring Adrian Hoven, Corny Collins and Paul Löwinger. It was shot partly in studios in Brussels and on location in Antwerp. The film's sets were designed by the art director Hans Zehetner. It is inspired by the British television series The World of Tim Frazer by Francis Durbridge, although the protagonist is shifted from a British structural engineer to a private detective.
British detective Tim Frazer heads to Antwerp to investigate the murderer targeting members of a smuggling gang. With the help of his fiancée Janine, who goes undercover in a bar, Frazer eventually unmasks the mysterious criminal leader "Mister X" following a dramatic pursuit through the city's harbour.