Christian science fiction is a subgenre of both Christian literature and science fiction, in which there are strong Christian themes, or which are written from a Christian point of view. These themes may be subtle, expressed by way of analogy, or more explicit. Major influences include early science fiction authors such as C. S. Lewis, while more recent figures include Stephen Lawhead and Tim LaHaye. Authors writing in this subgenre face particular difficulties reconciling aspects of science with their Christian beliefs, which may lead to difficulties having their work accepted by the wider science fiction community.

The term is not usually applied to works simply because most or all of the characters are Christian, or simply because the author is Christian.