Self-Government Boards of Appeals (SBoAs) act, within their statutory competence, as bodies of higher instance, within the meaning of the Code of Administrative Procedure and the Tax Ordinance Act, in individual public administration matters falling within the jurisdiction of local governments, unless specific provisions of law provide otherwise. In view of this, inevitably, their adjudicatory practice relies, among other things, on the direct application of general principles articulated in the Code of Administrative Procedure and the Tax Ordinance Act, especially in terms of ensuring active participation of the parties in the appeal proceedings. Given the specificity of the court operating as a quasi-judicial body, the article analyses the interplay between the general principles related to active participation of the parties to proceedings and outlines difficulties (and challenges) related to the issues discussed. The study was conducted by employing the formal and dogmatic method, as well as auxiliary legal-historical method, with a view to presenting the normative context of the adopted legal solutions. Moreover, the conduced analysis of court and tribunal jurisprudence allowed inclusion of the practical aspects of the general principles in question and their application.