The aim of this study was to examine the relationship between psychological resilience and mental well-being in young adults, with particular emphasis on the mediating role of rumination. The study involved 174 young adults aged 18 to 35. Participants completed the Psychological Resilience Scale, the Rumination-Reflection Questionnaire, and the Mental Well-Being Questionnaire. Statistical analyses revealed significant correlations: psychological resilience was negatively associated with rumination and positively associated with mental well-being. Rumination, in turn, was negatively related to well-being. Mediation analysis confirmed that rumination mediates the relationship between resilience-particularly in the areas of somatization, emotional-social functioning, and attitudes toward injury-and mental well-being. The findings contribute to a deeper understanding of the psychological mechanisms underlying well-being in young adults and may inform both clinical practice and future research. Moreover, the results should be utilized in the development of prevention programs and public awareness campaigns aimed at increasing societal understanding of the factors that influence and shape psychological resilience. Understanding psychological mechanisms such as resilience and the tendency to ruminate may provide essential support for legislative initiatives undertaken at the national level in Poland. This knowledge can lead to the creation of more effective and tailored preventive and intervention strategies in the field of mental health, and help shape public policies that better address the psychological needs of the population.