Objectives: Vaccination skepticism and vaccination refusal both constitute global public health concerns. Systematic monitoring of public attitudes towards vaccination is crucial for maintaining a high vaccination coverage rate. The study aimed to identify and characterize homogenous social groups distinguished by attitudes toward preventive vaccinations. Material and Methods: Between October and November of 2021, a nationwide representative cross-sectional survey was conducted on a representative sample of 1560 inhabitants of Poland aged 15–39 years. The study questionnaire included 60 questions on public attitudes towards vaccines, vaccination, and the COVID-19 pandemic. Factor analysis was applied to identify the main dimensions of vaccination attitudes. Results: Factor analysis included 22 variables and yielded 3 factors or dimensions that accounted for 48.5% of the model’s variability. Young adults were assigned into 6 homogeneous groups based on these factors: 1) general trust in vaccination, 2) vaccine safety concerns, 3) trust in fake medical news regarding COVID-19 vaccination, and denying the COVID-19 pandemic. Groups I–IV differed by sociodemographic factors and vaccination coverage rates. Nearly 60% of the respondents expressed concern regarding various aspects of vaccination. Conclusions: Most of Poland’s young adults lack clearly defined attitudes towards vaccination. Attitudes towards vaccination can be divided into 6 heterogeneous groups. Int J Occup Med Environ Health. 2023;36(2):214–28