Isaac George Hawthorne (12 November 1912 – December 1992) was a Unionist politician in Northern Ireland. Hawthorne was schooled in Portadown and Sheffield before becoming a farmer. He was elected to Armagh County Council in 1947 as an Ulster Unionist Party member, holding his seat until 1958. In 1955, he was elected to the Parliament of Northern Ireland in a by-election in Central Armagh.