Colac can refer to:

• Colac, Victoria, a town in Australia
  • City of Colac, a former local-government area in Victoria, Australia
  • Shire of Colac, a former local-government area in Victoria, Australia
  • Shire of Colac Otway, a current local-government area in Victoria, Australia
  • Colac Botanic Gardens, in Colac, Australia
  • Colac railway station, in Colac, Australia
• Lake Colac in Victoria, Australia
• Colac (mountain), in the Italian Dolomites
• Colac Bay, New Zealand
• HMAS Colac, a ship of the Royal Australian Navy
• Kalach (food), spelled colac in Romania, traditional East Slavic bread, also common in Hungary, Romania, and Serbia