A psalter is a volume containing the Book of Psalms, often with other devotional material bound in as well, such as a liturgical calendar and litany of the Saints. Until the emergence of the book of hours in the Late Middle Ages, psalters were the books most widely owned by wealthy lay persons. They were commonly used for learning to read. Many Psalters were richly illuminated, and they include some of the most spectacular surviving examples of medieval book art.

The English term (Old English psaltere, saltere) derives from Church Latin. The source term is Latin: psalterium, which is simply the name of the Book of Psalms (in secular Latin, it is the term for a stringed instrument, from Ancient Greek: ψαλτήριον psalterion). The Book of Psalms contains the bulk of the Divine Office of the Roman Catholic Church. The other books associated with it were the Lectionary, the Antiphonary, and Responsoriale, and the Hymnary. In Late Modern English, psalter has mostly ceased to refer to the Book of Psalms (as the text of a book of the Bible) and mostly refers to the dedicated physical volumes containing this text.