Sudbury, town (parish), Babergh district, administrative and historic county of Suffolk, eastern England. It lies on the River Stour about 18 miles (29 km) west of Ipswich.
An important wool town during the Middle Ages, it has many half-timbered houses and three Perpendicular-style churches. Sudbury was first incorporated in 1554. As the worsted industry declined, silk weaving and coconut matting were introduced. Milling and brewing have also become important. The 18th-century English artist Thomas Gainsborough was born there in a house that is now an art centre. Pop. (2001) 11,933; (2011) 13,063.