Henley-on-Thamestown (parish), South Oxfordshire district, administrative and historic county of Oxfordshire, England, southeast-central England. It lies on the left bank of the River Thames . It lies at the foot of the Chiltern Hills, where the river is crossed by a fine stone bridge (1786).

The old town (incorporated 1526) has a medieval church and a wide market street. Georgian buildings are also well represented. The old town serves as the shopping centre of the modern riverside resort and residential town, which is especially famous as a rowing centre. The Henley Royal Regatta, which dates from 1839, is visited annually in July by international oarsmenrowing crews. Pop. (2001) 10,646; (2011) 11,619.