<p>Health education curricular analysis is an emerging approach for a systems level understanding of health literacy (HL) development, with previous findings highlighting international curricula trends in HL promotion for primary school aged children. A contemporary understanding of HL advancement during adolescent years would provide new knowledge and awareness of health behaviours during a critical time of transition in life. Analysing All-Island secondary level health education curricula in Ireland would encourage an understanding of needs and structure of HL, and could provide a starting point for shared dialogue and learning. Using content analysis, a comparison of secondary level health curricula in Ireland was undertaken. A repeated measures ANOVA was used to evaluate HL and health education exposure. There was a significant main effect of HL level (<i>p</i> &lt; .05), indicating the percentage of HL changed depending on the level it was measured at. Overall HL level did not differ between Republic of Ireland and Northern Ireland health education curricula. Limited functional HL development was found in a Northern Ireland post-primary health education context. Social health dominance was observed across the island, mirroring an international trend on HL development in schools. An All-Island emphasis on critical social HL in health education was established. More research into an Irish primary school curricular context, matched with emphasis on explicit and implicit delivery of health curriculum through teacher agency, could provide further extended insight. Collectively there is shared potential for significant shared dialogue towards an All-Island contextual approach to HL development.</p>