Red Alert is a 1958 novel by Peter George about nuclear war. The book was the basis for Stanley Kubrick's 1964 film, Dr. Strangelove or: How I Learned to Stop Worrying and Love the Bomb. Kubrick's film differs significantly from the novel in that it is a comedy.

Originally published in the UK as Two Hours to Doom – with George using the pseudonym "Peter Bryant" – the novel deals with the apocalyptic threat of nuclear war and the almost absurd ease with which it can be triggered. A genre of such topical fiction sprang up in the late 1950s – led by Nevil Shute's On the Beach – of which Red Alert was among the earliest examples.

Eugene Burdick and Harvey Wheeler's later bestseller Fail-Safe so closely resembled Red Alert in its premise that George sued on the charge of plagiarism, resulting in an out-of-court settlement. Both novels would inspire very different films that would both be released in 1964 by the same studio (Columbia Pictures).