This paper discusses the appellate procedure in tax law. The paper is divided into eight parts. At the end of the paper, the literature is listed. By defining the appeal, we came to the conclusion that it is a regular remedy. The right to appeal is regulated by the Constitution in the Republic of Croatia. The participants in the appeal proceedings are the appellant and the person invited to participate in the proceedings. Against the first-instance decision, the party has the right to express a complaint to the second-instance body. The second-instance body shall, ex officio or at the request of the taxpayer, include in the proceedings those persons whose legal interest may have been affected. The purpose of the appeal is to challenge the legality or regularity of the first-instance decision. A party may also file an appeal when the decision has not been rendered within the legally prescribed time limit. The second-instance body will resolve the matter on the basis of the facts established in the first-instance proceedings. When the second-instance decision is made, that procedure is completed, and the party has no right to use regular legal remedies. The devolutionary effect of an appeal enables a party who considers that the decision of the first-instance body has violated his rights to demand supervision and legality from hierarchical higher bodies. Finances are of great importance in many countries and as such are very sensitive and have special weight, especially in judgments and decisions. Decisions must be made within a reasonable and specified time, be made correctly and truthfully, taking into account the evidence. Tax law in the Republic of Croatia has begun to be studied more thoroughly in the last few years. Education is crucial in the tax relationship of the parties. It is important to emphasize that a party is entitled to extraordinary remedies only in cases prescribed by law.