The Didache (Greek: Διδαχή) or The Teaching of the Twelve Apostles (Didachē means "Teaching") is a brief early Christian treatise, dated by most scholars to the mid to late first century.

The text, parts of which constitute the oldest surviving written catechism, has three main sections dealing with Christian ethics, rituals such as baptism and Eucharist, and Church organization. It is considered the first example of the genre of the Church Orders.