Upper Winchendon or Over Winchendon is a village and civil parish in the Aylesbury Vale District of Buckinghamshire, England. It is about 1.5 miles (2.4 km) south of Waddesdon and 4.5 miles (7 km) west of Aylesbury.
On 17 November 2017 a mid-air collision between an aeroplane and a helicopter just outside the village lead to the Waddesdon Manor air incident.
The name "Winchendon" is derived from the Old English for "hill at a bend". Collectively the villages of Upper Winchendon and Nether Winchendon (or Lower Winchendon) were called Wichendone.