St Arnaud () is a town in the Wimmera region of Victoria, Australia, 244 kilometres north west of the capital Melbourne. It is in the Shire of Northern Grampians local government area. At the 2011 census, St Arnaud had a population of 2,619.
It is named after French marshal Jacques Leroy de Saint Arnaud, commander-in-chief of the army of the East. It is one of quite a number of towns, streets etc. named after people and places of the Crimean War.