Lieutenant-General Richard Lambart, 6th Earl of Cavan (died 2 November 1778) was an Anglo-Irish peer and soldier.
He joined the Army and became a Major-General in 1772 and a Lieutenant-General in 1777. He was appointed Colonel of the 55th Foot on 3 August 1774, transferring as Colonel to the 15th Foot on 7 September 1775, an appointment he held until his death.
He was elected to the Parliament of Ireland in 1773.
He died in 1778 and was buried in St Patrick's Cathedral. He married twice: firstly his cousin Sophia, daughter of Oliver Lambart (a younger son of Charles Lambart, 3rd Earl of Cavan); and secondly Elizabeth, the daughter and coheiress of William Davies (Commissioner of the Navy), with whom he had a son and a daughter. He was succeeded by his son Richard Lambart, 7th Earl of Cavan.
- "55th Regiment of Foot-Richard Lambart, 6th Earl of Cavan". British Empire (Stephen Luscombe]. Retrieved 6 July 2016.
- Lodge, John. The Peerage of Ireland:Volume I. p. 361.