Aim: This study analyzes factors associated with dimensions of health literacy (HL) functional, communicative and critical among public health service users with chronic non-communicable diseases. Methods: A cross-sectional analytical research was carried out in Piracicaba, São Paulo, Brazil, with adults and older adults attending Family Health Units (FHU). Data were collected by oral exam (CPOD and CPI) and a questionnaire on systemic conditions, sociodemographic factors, health behaviors and HLS (HLS-14). The outcomes consisted of functional, communicative, and critical HL dimensions dichotomized by median (high and low), which were analyzed by chi-square test (p<0.05) to find associations with the variables studied. Results: The study sample comprised 238 FHU users with 62.7 (± 10.55) mean age, of which 47.5% (n=113) showed high functional HL, 50.0% (n=119) high communicative HL, and 46.2% (n=110) high critical HL. High functional HL was associated with men (p<0.05). Functional and communicative HL were associated with having higher education (p<0.001 and p=0.018, respectively). High communicative and critical HL were associated with regular use of dental and medical services (p<0.05). Individuals with low functional HL were more likely to present poor tooth brushing (p=0.020). High HL (in all three dimensions) was associated with regular flossing and having more teeth (p<0.05). Conclusion: Functional, communicative and critical HL were associated with health behaviors and clinical outcomes, whereas the functional dimension was also associated with sociodemographic factors. HL dimensions allowed to differentiate health-related factors.