In music, an ostinato [ostiˈnaːto] (derived from Italian: stubborn, compare English: 'obstinate') is a motif or phrase that persistently repeats in the same musical voice, usually at the same pitch. Well-known ostinato-based pieces include both classical compositions such as Ravel's Boléro and popular songs such as Donna Summer and Giorgio Moroder's "I Feel Love" (1977) and The Verve's "Bitter Sweet Symphony" (1997).

The repeating idea may be a rhythmic pattern, part of a tune, or a complete melody in itself. Both ostinatos and ostinati are accepted English plural forms, the latter reflecting the word's Italian etymology. Strictly speaking, ostinati should have exact repetition, but in common usage, the term covers repetition with variation and development, such as the alteration of an ostinato line to fit changing harmonies or keys.

Within the context of film music, Claudia Gorbman defines an obstinate as a repeated melodic or rhythmic figure that propel scenes that lack dynamic visual action.