A Study in Terror is a 1965 British thriller film directed by James Hill and starring John Neville as Sherlock Holmes and Donald Houston as Dr. Watson. It was filmed at Shepperton Studios, London, with some location work at Osterley House in Middlesex.

Although based on Arthur Conan Doyle's characters, the story is an original one, which has the famous detective on the trail of Jack the Ripper. The story of A Study in Terror challenges Sherlock Holmes to solve these horrific crimes. This leads Holmes through a trail of aristocracy, blackmail and family insanity. Unlike Scotland Yard, and the real-life story, Holmes eventually discovers the true identity of the Ripper.

The film had its world premiere at the Leicester Square Theatre in the West End of London on 4 November 1965. A Study in Terror presents the first film appearance of Mycroft Holmes.