Currently you cannot get an Apostille for a Canadian Marriage Certificate. Since Canada has not signed the Apostille Convention the original process of Authentication and Legalization is still used to make a Canadian document valid for use in another country. Your Marriage Certificate will therefore first need to be authenticated by Global Affairs Canada and then legalized by the Embassy or Consulate of the country in which you will be using the Marriage Certificate. These two steps of authentication and legalization together are the equivalent of an Apostille in other countries.