Admiral Sir Ross Donnelly, KCB (1764 – 30 September 1840) was an Irish Royal Navy officer who is known for his service during the American War of Independence, French Revolutionary War and Napoleonic Wars. He was first lieutenant on HMS Montagu at the Glorious First of June and assumed command after the death of Captain James Montagu. Promoted to post captain in June 1795, Donnelly was given HMS Pegasus in which he participated in the action of 12 May 1796.