The Most Reluctant Convert: The Untold Story of C.S. Lewis is a 2021 British biographical drama film written and directed by Norman Stone, based on the 2016 stage play, C.S. Lewis on Stage: The Most Reluctant Convert, by Max McLean (which itself was based on Lewis' 1955 memoir Surprised by Joy). It is about the life and conversion of British writer, lay theologian, and Christian apologist C. S. Lewis, author of The Chronicles of Narnia series. The film stars McLean, Nicholas Ralph, Eddie Ray Martin, Richard Harrington, Amy Alexander, and Tom Glenister.

The film was released in the United States on November 3, 2021, and in the United Kingdom on November 7, 2021.

Director Norman Stone had previously directed 1985's Shadowlands, a film about the relationship between C. S. Lewis and American author Joy Davidman, for which he won a BAFTA for Best Single Drama (along with producer David M. Thompson).