Literacy is a crucial capacity that underpins and drives learning across the school curriculum. At a time of renewed interest in content-literacy integration, this mixed methods study examines how teachers think about and practice literacy across various disciplines and across primary and secondary schools. To do this, it draws on in-depth interviews (n=30) with primary and secondary teachers of disparate disciplines. These data are supplemented with an analysis of teachers’ (n=455) self-efficacy for the practices associated with disciplinary literacy instruction. The findings add to the limited pool of studies conducted outside secondary settings, highlighting inconsistencies in practices across stages of schooling and deep theory-practice gaps in the way literacy manifests across the disciplines. They suggest that subject specialities at secondary level do not confer an automatic advantage in understanding how literacy practices inform learning in a given discipline. Implications for continuing teacher education and research are outlined.