Sir Robert Vincent Monahan QC (11 April 1898 – 10 May 1975) was an Australian lawyer and judge who served on the Supreme Court of Victoria from 1955 to 1970.
He attended St Patrick's College, Ballarat, before going on to study law at the University of Melbourne.
He developed a reputation as one of Melbourne's leading personal injury and criminal defence lawyers.
On the court, Monahan mainly adjudicated criminal trials, personal injury matters, and divorce cases.
Outside of his work, his chief passion was horse racing – he once won £50,000 betting on the Irish Derby.