In music, syncopation is a variety of rhythms played together to make a piece of music, making part or all of a tune or piece of music off-beat. More simply, syncopation is "a disturbance or interruption of the regular flow of rhythm": a "placement of rhythmic stresses or accents where they wouldn't normally occur". It is the correlation of at least two sets of time intervals.

Syncopation is used in many musical styles, especially dance music. According to music producer Rick Snoman, "All dance music makes use of syncopation, and it's often a vital element that helps tie the whole track together".

Syncopation can also occur when a strong harmony is simultaneous with a weak beat, for instance, when a 7th-chord is played on the second beat of ³
₄ measure or a dominant chord is played at the fourth beat of a ⁴
₄ measure. The latter occurs frequently in tonal cadences for 18th- and early-19th-century music and is the usual conclusion of any section.

A hemiola (the equivalent Latin term is sesquialtera) can also be considered as one straight measure in three with one long chord and one short chord and a syncope in the measure thereafter, with one short chord and one long chord. Usually, the last chord in a hemiola is a (bi-)dominant, and as such a strong harmony on a weak beat, hence a syncope.