Background Over recent decades, the issue of same-sex civil unions has been discussed and then legally regulated in many European Union countries. In the case of Poland, this issue is still debated in the socio-political discourse. Methods The research presented in this article is aimed at analyzing the attitudes of Polish society towards legalization of same-sex registered partnerships. The study was nationwide and based on a quota sampling method (n = 2119). The data was collected in 2019. Results An analysis of the collected data showed that the support for legalizing same-sex partnerships is not accepted by the majority of voters in Poland. However, there are differences between supporters of various political groups as well as between those who declare left-wing or right-wing views. Conclusions For opponents of equal rights for homosexuals and heterosexuals, a crucial issue is the objection to same-sex marriage. The voters of left-wing parties and people declaring left-wing political leanings were more likely to accept other forms of marriage, although for the majority of them, marriage can be only a union between a woman and a man. Policy Implications The resistance of the ruling party Law and Justice, a conservative one, against legalization of same-sex partnerships and making decisions aimed at LGBT community, for instance introducing “LGBT-free zones,” are one of the elements encouraging its electorate.