Frederick Montagu PC FRS (July 1733 – 30 July 1800) was a British Whig MP.
His father Charles Montagu (of Papplewick) was auditor-general of the duchy of Cornwall, while Frederick was Prince of Wales; was MP for Westminster in 1722, for St. Germans in 1734, for Camelford in 1741, and for Northampton in 1754, and died on 29 May 1759. Frederick's mother, Ann Colladon Montagu, well known in society after her husband's death, was an intimate friend of Mary, dowager-countess of Gower (the widow of John Leveson-Gower, 1st Earl Gower), and of Mary Delany, in whose published 'Correspondence' she frequently figures as 'my Mrs Montague', in order to distinguish her from the better known Elizabeth Montagu. Her London residence was in Hanover Square. She died 31 May 1780.
Frederick, after being educated at Eton and Trinity College, Cambridge 8 February 1750. He seems to have won Paris's college declamation prize, and his oration was published at the request of the master and fellows as 'Oratio in laudes Baconi,' Cambridge, 1755, 4to. He graduated Master of Arts (MA) per lit. reg. in 1757.
At Cambridge Montagu, made the acquaintance of the poets Gray and Mason, which he sedulously cultivated afterwards. To his influence Mason owed his appointment to a canonry at York in 1762. Admitted a barrister of Lincoln's Inn in 1757, Montagu became a bencher in 1782. He was MP for Northampton from 1759 to 1767, in succession to his father, and for Higham Ferrers from 1768 to 1790.