Walter Stewart (or Steward) was a Scottish courtier and politician who sat in the House of Commons from 1624 to 1625.
He was the third son of Walter Stewart, 1st Lord Blantyre.
Stewart was admitted to Gray's Inn on 9 March 1620 when he was a Gentleman of the Privy Chamber to James I. In 1624, he was elected Member of Parliament for Monmouth Boroughs but was unseated on petition on 28 March 1624 on the objection that he was a "Scotchman" and not naturalised. However he was re-elected MP for Monmouth in 1625 without further question.
Stewart is also said to have been a qualified doctor. He left England in 1649 for France, where he was court physician to Queen Henrietta Maria. He died in or by 1657.
Stewart married Sophia, a dresser to Queen Henrietta Maria. Their children included Frances Stewart, Duchess of Richmond and Sophia Bulkeley.