This study reports findings from an exploration of the literacy practices of 10 high school science teachers. Based on observations of teachers' instruction, we report teachers' use of text, evidence-based vocabulary and comprehension practices, and grouping practices. Based on interviews with teachers, we also report teachers' perceptions regarding their role in implementing literacy instruction and the alignment of these perceptions with their practices. In total, we observed for 3,167 min across teachers. Coding of observations revealed that teachers rarely used expository text and implemented a minimal amount of vocabulary and comprehension strategy instruction. They used a variety of grouping practices but most often utilized whole-class instruction and independent work. Coding of interviews revealed that teachers supported the idea of integrating text and literacy instructional practices into their lessons but perceived a wide range of barriers to implementing these practices. We provide implications and directions for future research.