Ralph Weldon (baptised 1606 – 1676) was an English politician who sat in the House of Commons from 1654 to 1656. He fought in the Parliamentary army in the English Civil War.
Weldon was the son of Sir Anthony Weldon of Swanscombe, Kent. He was admitted at Jesus College, Cambridge on 24 November 1620. He became a commander in the Parliamentary Army at Taunton, Somerset, and took part in the siege of Bristol in 1645. He gave up his command to become Governor of Plymouth in 1645.
In 1654, Weldon was elected Member of Parliament for Kent in the First Protectorate Parliament and was re-elected MP for Kent in 1656 for the Second Protectorate Parliament.