Gospel originally meant the Christian message ("the gospel"), but in the 2nd century it came to be used also for the books in which the message was reported. In this sense a gospel can be defined as a loose-knit, episodic narrative of the words and deeds of Jesus, culminating in his trial and death and concluding with various reports of his post-resurrection appearances. Modern biblical scholars are cautious of relying on the gospels uncritically, but nevertheless, they provide a good idea of the public career of Jesus, and critical study can attempt to distinguish the original ideas of Jesus from those of the later Christian authors.

The canonical gospels are the four which appear in the New Testament of the Bible. They were probably written between AD 66 and 110. All four were anonymous (with the modern names of the "Four Evangelists" added in the 2nd century), almost certainly none were by eyewitnesses, and all are the end-products of long oral and written transmission. Mark was the first to be written, using a variety of sources. The authors of Matthew and Luke both independently used Mark for their narrative of Jesus's career, supplementing it with a collection of sayings called "the Q source", and additional material unique to each. There is near-consensus that John had its origins as the hypothetical Signs Gospel thought to have been circulated within a Johannine community. The contradictions and discrepancies between the first three and John make it impossible to accept both traditions as equally reliable.

Many non-canonical gospels were also written, all later than the four canonical gospels, and like them advocating the particular theological views of their various authors. Important examples include the gospels of Thomas, Peter, Judas, and Mary; infancy gospels such as that of James (the first to introduce the perpetual virginity of Mary); and gospel harmonies such as the Diatessaron.