Within the internal European market, member states are allowed to implement their own tax legislation. This has a neutral effect on the domestic situation. Member states do not want taxpayers to pay double taxes or no taxes at all. If several member states are involved, double taxation or double tax evasion may occur. This dissertation examined whether the principles of internal market neutrality can provide a solution. If the internal market is approached in the same way as the market of an individual member state, what legislative changes should be made to prevent tax evasion and double taxation?