This qualitative inquiry examined 14 secondary preservice teachers' emerging understandings of disciplinary literacy. Data included preservice teachers' written reflections and annotated lesson plans, which were analyzed for understanding of discipline-specific habits of thinking, texts, reading and writing demands of academic texts, language and vocabulary, and instructional tools. Findings revealed the current literacy course provided limited understanding of disciplinary literacy, exposing areas for course improvement. Annotated lesson plans and structured reflections were useful tools to help preservice teachers examine instructional decisions and strengthen understanding of disciplinary literacy. Limitations included small sample size, minimal sources of triangulated data, short duration of study, and inadequate focus on disciplinary literacy as the mainstay of the course. Implications for strengthening teacher preparation through course reframing and collaborative partnerships are discussed.