Joshua Gordon MacArthur (October 19, 1911 – July 23, 1980) was a carpenter, farmer and political figure on Prince Edward Island. He represented 2nd Prince in the Legislative Assembly of Prince Edward Island from 1970 to 1976 as a Liberal.
He was born in Poplar Grove, Prince Edward Island, the son of George Percy MacArthur and Caroline Alice Adams. He was married twice: to Edna Noye in 1933 and to Vera Jannette Smallman, the daughter of Forrest Phillips, in 1969.
First elected in the 1970 election, he won by a margin of just eight votes over Progressive Conservative leader George Key. His victory was subsequently confirmed on a judicial recount.
MacArthur resigned due to poor health in 1976. He died at the Stewart Memorial Health Centre in Tyne Valley at the age of 68.