Guns in the Heather is a 1969 Walt Disney adventure film directed by Robert Butler and produced by Ron Miller. It stars Kurt Russell, Glenn Corbett and Alfred Burke. It was originally broadcast in parts on Walt Disney's Wonderful World of Color in the United States under the title Guns in the Heather, then re-edited for a European theatrical release under the English title, The Secret of Boyne Castle. It was re-broadcast on American television in 1978 under the title Spy-Busters. The story is based on the 1963 novel Guns in the Heather, by Lockhart Amerman.

The film was primarily shot on location in Ireland (St. Flannan's College in Ennis, Corkscrew Hill, Corofin and Kilfenora, County Clare feature) with additional scenes shot at Pinewood Studios near London, England.