Sydenham's chorea, also known as rheumatic chorea, is a disorder characterized by rapid, uncoordinated jerking movements primarily affecting the face, hands and feet. Sydenham's chorea is an autoimmune disease that results from childhood infection with Group A beta-haemolytic Streptococcus. It is reported to occur in 20–30% of people with acute rheumatic fever and is one of the major criteria for it, although it sometimes occurs in isolation. The disease occurs typically a few weeks, but up to 6 months, after the acute infection, which may have been a simple sore throat (pharyngitis).

Sydenham's chorea is more common in females than males, and most cases affect children between the ages of 5 and 15 years of age. Adult onset of Sydenham's chorea is comparatively rare, and the majority of the adult cases are recurrences following childhood Sydenham's chorea.

It is historically one of the conditions called St Vitus' dance.