Ronald St. John Macdonald, CC (August 20, 1928 – September 7, 2006) was a Canadian legal academic and jurist.
Born in Montreal, the son of R. St. John Macdonald and Elizabeth Smith, he served as a Sub-Lieutenant in the Royal Canadian Navy (Reserve) during World War II.
He was the only non-European judge of the European Court of Human Rights, where he served from 1980 to 1998.
He was the first Westerner appointed as Honorary Professor of Law at China's Peking University.
In 1999, he was awarded the Canadian Bar Association's Ramon John Hnatyshyn Award for Law in recognition of "outstanding contribution to the law or legal scholarship in Canada".