Poor health literacy (HL) is associated with poor health behaviours and outcomes. The aim of the study was to investigate the effect of socioeconomic status on HL and nutrition literacy (NL) in Greece. This is a cross-sectional study which took place in Attica, Greece. 1281 individuals, aged ≥18 years of both sexes, participated. The European Health Literacy Questionnaire and the Greek version of the Nutrition Literacy Scale were used. Linear regression analysis revealed that education was significantly positively associated with HL (p = 0.002) and medium annual income was significantly associated with higher HL (p = 0.024), in contrast to low annual income. Education (p < 0.001) was significantly positively associated with NL. Unskilled particpants had lower NL compared to skilled paricipants (p = 0.021) and participants with medium annual income had significantly higher NL (p = 0.003) in comparison to participants with low annual income. Socioeconomic inequalities seem to negatively associate with HL and NL in Greece.