The Gospel of Philip is one of the Gnostic Gospels, a text of New Testament apocrypha, dated to around the 3rd century but lost in modern times until an Egyptian man rediscovered it by accident, buried in a cave near Nag Hammadi, in 1945.

The text is not related to the canonical gospels and is not accepted as canonical by the Christian church. Although it may seem similar to the Gospel of Thomas, scholars are divided as to whether it is a single discourse or a collection of Valentinian sayings. Sacraments, in particular the sacrament of marriage, are a major theme. As in the other gnostic texts, the Gospel of Thomas and Gospel of Mary, the Gospel of Philip defends the tradition that gives Mary Magdalene special insight into Jesus' teaching, but does not support "twenty-first-century inventions concerning Mary Magdalene as Jesus' wife and mother of his offspring."

Nevertheless, novels such as Dan Brown's The Da Vinci Code have encouraged the popular theory that Jesus was married to Mary Magdalene. The Ancient Greek manuscript describes Jesus as Mary's "koinonos", or "companion", which may sometimes imply a sexual relationship, but is always used as "a metaphor for a deeper, spiritual partnership".