- The character of Crowley in Good Omens has obviously either read The Screwtape Letters or else was at Tempters' College being taught by Screwtape. Crowley's realisation that the world is too big for craftmsmanship and that "you can't pick the buggers off one by one any more" as there are far too many of them is a restating of Screwtape's maxim - get the leaders and the herd will follow. The bureaucratic nature of Crowley's Hell - and by extention Aziraphile's Heaven - is also straight out of Screwtape.
- Miss Wormwood, Calvin's teacher on Calvin and Hobbes, is named after the apprentice devil Screwtape writes to.
- The album "Dear Wormwood" by The Oh Hellos was partially inspired by the book.
Referenced By / The Screwtape Letters