Robert MacCarty, Viscount Muskerry (1698 – 19 September 1769) was an Irish officer of the Royal Navy, and a colonial administrator. He belonged to the MacCarthy of Muskerry dynasty.
Muskerry was the son of Donough MacCarty, 4th Earl of Clancarty, and Lady Elizabeth, daughter of Robert Spencer, 2nd Earl of Sunderland, and was educated at St Paul's School. His father was attainted in 1691 after supporting the Catholic James II, with his titles forfeited, and Muskerry was never allowed to succeed in the earldom. However, he continued to be known under his courtesy title Viscount Muskerry. From 1733 to 1734 he served as Commodore Governor of Newfoundland, becoming the first Irishman to hold this post. In 1747 he was excepted from the Act of Indemnity which pardoned Jacobites.
Muskerry married firstly Joanna, daughter of Henry Player, in 1722. They had no children and she died in 1759. He married as his second wife Elizabeth Farnelly. They had one daughter. Lord Muskerry died in Boulogne, France, in September 1769.