Despite the fact that the fundamental principles of fairness and neutrality in taxation have been leading starting points in the legislative work, legal developments have meant that current tax legislation is in many cases perceived as both unfair and non-neutral. This development has motivated new legislation against perceived unfair taxation, as well as an extensive investigation for a new, more neutral corporate tax. One possible reason for the legal development that has proved contrary to the fundamental principles of tax law, which are clearly stated in the preparatory works, may be the Swedish tradition of interpreting tax law in the light of civil law, which in recent years has also proved to include both international accounting law and financial theory. Through such an interpretation, the law is given its content with reference to non-tax law, extraneous facts and the possibilities of relating to tax law principles in the application of the law are thus limited. In this research project, the Swedish tax law interpretation tradition is analyzed against the background of accepted legal theory, and in comparison with the Anglo-Saxon and continental European interpretation tradition of tax legislation. The research is important because it presents legal arguments for alternative ways of interpreting tax law, which in Sweden may eventually lead to a legal development that is more compliant in relation to the purpose of the legislation - which would benefit both the legislator and the legal practitioner.