The HLS-EU-Q47 serves as a self-reported instrument designed for the consistent evaluation of health literacy levels. This research sought to adapt the HLS-EU-Q47 into Slovenian and evaluate its reliability and validity within the Slovenian population. The questionnaire underwent forward translation into Slovenian, backward translation, and a preliminary pilot testing phase. The final Slovenian adaptation was distributed by mail to a random sample of 2500 adult citizens in the Republic of Slovenia. Reliability assessment involved calculating Cronbach’s alpha coefficients for the single-factor, three-factor, four-factor, and twelve-factor structures, which correspond to overall health literacy, the three primary health domains, the four information processing skills, and their twelve combined subdomains, respectively. Validity was assessed through confirmatory factor analysis, univariate comparisons, and multivariable linear regression. Out of the mailed questionnaires, 517 were returned (yielding a 21% response rate). The single-factor structure yielded the highest Cronbach’s alpha value (0.950), with progressively lower values for the three-factor, four-factor, and twelve-factor structures. Confirmatory factor analysis indicated that the twelve-factor structure achieved the best fit indices (CFI 0.812; RMSEA 0.067, CI 0.065 to 0.070), outperforming the three-factor, four-factor, and single-factor models. In the multivariable regression analysis, only the relationship between self-rated health status and the overall health literacy score reached statistical significance (p < 0.001). The Slovenian adaptation of the HLS-EU-Q47 demonstrates strong reliability as a measure of health literacy. Although all structural models exhibited acceptable fit, none met every validity standard completely. Participants more clearly distinguished among the three core health domains (healthcare, disease prevention, and health promotion) than among the four information processing skills (accessing, understanding, appraising, and applying).
