The study addresses the issues of exclusion from the supplementary part of the Polish pension system. The main goals of the research are: 1) characterising retirement exclusion as a specific type of financial exclusion, and 2) identifying and assessing key determinants of retirement exclusion in the supplementary part of the Polish pension system. The article is epistemological and classifying in nature. In the review part, the research methods used are based on a critical analysis of the literature and a synthesis of its conclusions. The main part is based on a meta-analysis of the results of surveys regarding pension awareness and propensity to save, elements of the economic analysis of law, and analysis of existing data. The presented considerations lead to the formulation of arguments, that justify the thesis that the scale and extent of retirement exclusion in the supplementary part of the Polish pension system are a derivative of factors included in four meta-categories: 1. low pension awareness, 2. low saving potential, 3. low propensity to save, and 4. limited availability of pension products.