Sir Isaac Penington[1] (c. 1584 – 16 December 1661)[2] was an English politician who sat in the House of Commons from 1640 to 1653.

He and his wife, Mary, the widow of Roger Wilkinson, a Citizen of the City of London,[3] were both staunch Puritans.

[6] On 16 August 1642 Parliament appointed him Lord Mayor of London after removing the Royalist Sir Richard Gurney, 1st Baronet from the position.

From 1650 he was the sole representative of the City of London in the Rump Parliament until it was forcibly ejected by Oliver Cromwell on 30 April 1653.

[9] After the Restoration, he was tried for high treason and sentenced to life imprisonment in the Tower of London, where he died on the night of 16 December 1661.