Sir Matthew Lamb, 1st Baronet (1705 – 6 November 1768) was a British barrister and politician. He was the grandfather of Prime Minister William Lamb, 2nd Viscount Melbourne.
Lamb was the son of Matthew Lamb, of Southwell, Nottinghamshire, and nephew of Peniston Lamb. His brother was Robert Lamb, bishop of Peterborough. He sat as Member of Parliament for between 1741 and 1747 and for Peterborough between 1747 and 1768. In 1755 he was created a Baronet, of Brocket Hall in Hertfordshire.
He married with Charlotte, daughter of Thomas Coke. He died in November 1768 and was succeeded in the baronetcy by his son Peniston, who was raised to the peerage as Viscount Melbourne in 1770. His daughter Charlotte married Henry Belasyse, 2nd Earl Fauconberg.