Baron Leighton of St Mellons, of St Mellons in the County of Monmouth, is a title in the Peerage of the United Kingdom. It was created in 1962 for the Welsh shipping magnate Sir Leighton Seager, 1st Baronet. He was the son of Sir William Henry Seager. Seager had already been created a Baronet, of St Mellons in the County of Monmouth, in 1952. As of 2010[update] the titles are held by his grandson, the third Baron, who succeeded his father in 1998.