Sir John Owen of Clenennau (c. 1600–1666), was a Welsh landowner from Anglesey, who served with the Royalist army in the Wars of the Three Kingdoms, during which he held various commands in North Wales.

[3] Owen's background connected him with a tradition of High Anglicanism maintained by gentry families in Wales through much of the 17th century and centred on figures like Francis Mansell, principal of Jesus College, Oxford.

[4] After a period of military service, Owen inherited Clenennau on his mother's death in 1626, along with the large Maurice estates in south Caernarfonshire, Merioneth, and Anglesey.

Charles I authorised him to use county funds to raise and equip a regiment of foot in the three shires of Gwynedd, though local opposition meant that the unit was not ready until May 1643.

Following Thomas Myddleton's invasion of Wales in the winter of 1644 Owen was knighted by Charles at Oxford and was made Governor of the strategic walled town of Conwy.

[6] In the immediate aftermath of the war he retired to Clenennau; he was fined heavily by Parliament but rejected an offer from Rupert to lead a Welsh brigade in French service.

[3] By 1648 prospects of a peace settlement appeared in danger; Charles made an agreement with the Engager faction of the Parliament of Scotland to invade England and restore him, while elements of the Parliamentarian army were mutinous over arrears of pay.

A revolt over pay led by Major-General Rowland Laugharne began in South Wales in March 1648, which became overtly political when the rebels made contact with Charles.

Most Royalists chose to abide by the terms of their surrender and avoided involvement: Owen was said to have initially considered joining Laugharne, but was persuaded to attempt to spread the rebellion to Caernarfonshire.

[11] At trial in February 1649 he was condemned to death; he is supposed to have commented that "it was a very great honour to a poor gentleman of Wales to lose his head with such noble lords" and swore "that he was afraid they would have hanged him".