The Shire of Colac Otway is a local government area in the Barwon South West region of Victoria, Australia, located in the south-western part of the state. It covers an area of 3,438 square kilometres (1,327 sq mi) and in June 2018 had a population of 21,503. It includes the towns of Apollo Bay, Beeac, Beech Forest, Birregurra, Colac, Cressy, Forrest, Johanna, Kennett River, Lavers Hill, Warrion and Wye River. It came into existence on 23 September 1994 through the amalgamation of the local government areas of City of Colac, Shire of Colac, part of the Shire of Otway and part of the Shire of Heytesbury.

The Barwon South West is an economic rural region located in the southwestern part of Victoria, Australia. The Barwon South West region stretches from the tip of the Queenscliff Heads to the border of South Australia. It is home to Victoria’s largest provincial centre, Geelong and the major centres of Aireys Inlet, Apollo Bay, Camperdown, Colac, Hamilton, Lorne, Port Campbell, Port Fairy, Portland, Torquay and Warrnambool. It draws its name from the Barwon River and the geographic location of the region in the state of Victoria.