This article analyses the practice of the Polish administrative courts with respect to application of the Vienna Convention on the Law of Treaties, based on a case study of the judgment of the Voivodship Administrative Court in Warsaw of 6 May 2014 (case no. II SA/Wa 117/14), which concerned the recognition of distance learning degrees awarded by Ukrainian universities pursuant to the 1972 Prague Convention. It is argued herein that the reasoning of the court suffers from four major drawbacks: 1) it is at variance with the text, object and purpose of the Prague Convention; 2) it does not take into account the practice in the application of that treaty; 3) it misinterprets the silence of the preparatory work to the Prague Convention on certain issues; and 4) it is inconsistent with international judicial decisions as regards the interpretation of the “special meaning” of one of the terms used in the Convention.