Officium Defunctorum is a musical setting of the Office of the Dead composed by the Spanish Renaissance composer Tomás Luis de Victoria in 1605. The texts have also been set by other composers including Morales.
Victoria includes settings of the movements of the Requiem Mass, accounting for about 26 minutes of the 42 minute composition, and the work is sometimes referred to as Victoria's Requiem. However, it is not his only requiem, in 1583 Victoria composed and published a book of Masses, reprinted in 1592, including a Missa pro defunctis for four-part choir.