William de Botreaux, 3rd Baron Botreaux (1389–1462) was a prominent baron in Somerset and the south-west of England. He inherited from his father the barony by writ of Botreaux as well as substantial family landholdings which included a moiety of the feudal barony of North Cadbury, Somerset, in the parish church of which capital manor he was buried, as he requested in his will.
He was born on 20 February 1389 at Walton, Kilmersdon, Somerset, the son of William de Botreaux, 2nd Baron Botreaux (1367–1395) by his wife Elizabeth St. Lo, daughter and co-heiress of Sir John St. Lo (Latinised to St. Laudo) of Newton St Loe, Wiltshire (now in Somerset), by his second wife Margaret Clyvedon, daughter and heiress of John Clyvedon. Elizabeth was sole heiress of her mother and survived her husband, her death having occurred on 4 September between 1409 and 1458.
He was summoned to parliament on several occasions, the first time being on 1 December 1412, aged 23, and lastly on 23 May 1461, aged 72. He attended King Henry V (1413–1422) in France during the Battle of Agincourt (1415).
In 1435 he was appointed by Richard, Duke of York (d.1460), father of the future King Edward IV (1461–1483), as forester of the royal forests of Exmoor and of Neroche, Somerset, as is recorded in the following charter in French surviving in the British Library summarised in Harleian Charter 43 E 47:
The Barons Botreaux held a manor at Molland Bottreaux (sic), on the southern foothills of Exmoor. The forest of Neroche is situated in the Blackdown Hills, Somerset, to which was formerly appended Castle Neroche in the parish of Curland, near Staple Fitzpaine.