Sir Lambert Blackwell, 1st Baronet (died 1727) of Sprowston Hall, Norfolk, was an English diplomat and Whig politician who sat in the House of Commons from 1708 to 1710. Blackwell was one of the younger of the seventeen children of Captain , of Mortlake, Surrey and his wife Elizabeth Smithsby, daughter of James Smithsby. His father was an active Parliamentary officer from 1650 to 1658, and in 1688 was Governor of Pennsylvania. In 1697, Blackwell was made Knight Harbinger and Gentleman of the Privy Council, being Knighted on 18 May 1697. He married before February 1698 Elizabeth Herne, second daughter of Sir Joseph Herne, of London, Merchant, and his wife Elizabeth Frederick, daughter of Sir John Frederick, Lord Mayor of London from 1661 to 1662.