The present paper is devoted to the question of literary onomastics in the texts of a bilingual author. In discussing this problem, we focus on how literary characters are named in selected dramas by Tadeusz Rittner, which have both a Polish and a German version. A detailed analysis includes a comparison of names and surnames used by the author to identify his characters. We indicate differences in the choice of specific types of proper names and in their forms, which result from different customs and onomastic systems in each of Rittner’s languages, as well as from separate Polish and German linguistic etiquettes, determining the use of particular proper names. In addition, the analyses emphasize Rittner’s attention to onomastic and cultural reality that he introduced to his works, which confirms his linguistic and communicative competence in both Polish and German in this domain.