The purpose of this article is to present the regulations on supplementary claims applicable under the Polish and German law. The concept of supplementary claims under the Polish law refers to claims regulated in Articles 224 to 225 of the Polish Civil Code. Under German law, the core of the regulations governing the types and scope of these claims is contained in the text of §§ 987 to 993 of the BGB. On the grounds of both the analysed legal orders, one can notice numerous similarities regarding the way these claims are shaped. The most fundamental is the desire to provide increased protection for the good faith possessor and to tighten the liability of the person in possession of the thing, who is already aware of a vindicatory action against them or is in bad faith. Notwithstanding the foregoing, the analysis of the solutions for supplementary claims also allows us to see significant differences, expressed primarily in the much more comprehensive regulation of the issue in question in the German law. The article offers a comparative legal analysis of the solutions functioning on the grounds of both these legal orders and conclusions.