A double tax treaty, sometimes called a double tax convention, is a means to help eliminate the possibility of having to pay taxes twice on the same source of earned income. Most countries have these sorts of treaties in place. The treaties can also provide a means of having certain types of treatment when it comes to trading and investing across borders. It helps to greatly diminish unfair taxation rates that companies from certain countries may have to face. They protect the taxpayers, as well as the rights of the government for fair taxation.