Background: Health literacy (HL) is a crucial determinant of population health; however, disparities persist in multilingual settings. In South Tyrol, Italy, where German- and Italian-speaking populations coexist within a unified health care system, HL disparities may reflect differences in language, culture, and digital engagement. Objective: This study investigated whether the usage of digital health information mediates the relationship between language group and HL and examined informational trust and other sociodemographic factors as covariates of HL. Methods: Data were obtained from a population-based survey conducted in South Tyrol, Italy. The analytical sample comprised 1500 participants with adequate responses to the 16-item Health Literacy Survey European Union Questionnaire (HLS-EU-Q16) instrument and an identified language group. Mediation analysis was performed using PROCESS Model 4 (5000 bootstrap samples), with use of digital health information as the mediator, language group as the predictor, and HL as the outcome. Covariates included age, sex, education, self-rated health, trust in professional information sources, and trust in health information on the internet. Results: Italian-speaking participants showed significantly higher HL scores (mean 12.54, SD 3.31 vs mean 11.56, SD 3.48 on a 0-16 scale;