A hymnal or hymnary is a collection of hymns, usually in the form of a book, called a hymnbook (or hymn book). They are used in congregational singing. A hymnal may contain only hymn texts (normal for most hymnals for most centuries of Christian history); written melodies are extra, and more recently harmony parts have also been provided.

Hymnals are omnipresent in churches but are not often discussed; nevertheless, liturgical scholar Massey H. Shepherd once observed: "In all periods of the Church's history, the theology of the people has been chiefly molded by their hymns."

Since the twentieth century, singer-songwriter hymns have become common, but in previous centuries, generally poets wrote the words, and musicians wrote the tunes. The texts are known and indexed by their first lines ("incipits") and the hymn tunes are given names, sometimes geographical (the tune "New Britain" for the incipit "Amazing Grace, how sweet the sound"). The hymnal editors curate the texts and the tunes. They may take a well-known tune and associate it with new poetry, or edit the previous text; hymnal committees are typically staffed by both poets and musicians. Some hymnals are produced by church bodies and others by commercial publishers.

In large denominations, the hymnal may be part of a coordinated publication project that involves several books: the pew hymnal proper; an accompaniment version (e.g. using a ring binder so that individual hymns can be removed and sit nicely on a music stand); a leader's guide (e.g. matching hymns to lectionary readings); and a hymnal companion, providing descriptions about the context, origin and character of each hymn, with a focus on their poets and composers.

In some hymnals, the front section is occupied by service music, such as doxologies, three-fold and seven-fold amens, or entire orders of worship (Gradual, Alleluia, etc.). A section of responsorial psalms may also be included.

Hymnals usually contain one or more indexes; some of the specialized indexes may be printed in the companion volumes rather than the hymnal itself. A first line index is almost universal. There may also be indexes for the first line of every stanza, the first lines of choruses, tune names, and a metrical index (tunes by common meter, short meter, etc.). Indexes for composers, poets, arrangers, translators, and song sources may be separate or combined. Lists of copyright acknowledgements are essential. Few other books are so well indexed; at the same time, few other books are so well memorized. Singers often have the song number of their favorite hymns memorized, as well as the words of other hymns. In this sense, a hymnal is the intersection of advanced literate culture with the persistent survival or oral traditions into the present day.

The earliest hand-written hymnals are from the Middle Ages in the context of European Christianity, although individual hymns such as the Te Deum go back much further. The Reformation in the 16th century, together with the growing popularity of moveable type, quickly made hymnals a standard feature of Christian worship in all major denominations of Western and Central Europe. The first known printed hymnal was issued in 1501 in Prague by Czech Brethren (a small radical religious group of the Bohemian Reformation) but it contains only texts of sacred songs. The Ausbund, an Anabaptist hymnal published in 1564, is still used by the Amish, making it the oldest hymnal in continuous use. The first hymnal of the Lutheran Reformation was Achtliederbuch, followed by the Erfurt Enchiridion. An important hymnal of the 17th century was Praxis pietatis melica.

Market forces rather than denominational control have characterized the history of hymnals in the thirteen colonies and the antebellum United States; even today, denominations must yield to popular tastes and include "beloved hymns" such as Amazing Grace and Come Thou Fount of Every Blessing, in their hymnals, regardless of whether the song texts conform to sectarian teaching.