The present study examined middle school teachers' perceptions of literacy demands in their disciplines and specific literacy strategies they used to teach their disciplines. The eight participants in this multiple case study included 2 middle school teachers from each of 4 disciplines (i.e., English/language arts, science, social studies, and mathematics) who had completed 6 weeks of online professional development on disciplinary literacy. Data sources comprised 2 classroom observations and 2 semi-structured interviews following observations for each of the 8 teachers, as well as classroom and school artifacts. Qualitative analyses included within-case and cross-case themes. Findings indicated participants used a range of content area literacy and discipline-specific literacy instruction. Based on cross-case analysis, 4 themes emerged from the 4 discipline-based cases: (a) interdisciplinary literacy, (b) power in disciplinary language, (c) pedagogical tensions related to end of grade exams, and (d) individualized access. Two pedagogical tensions emerged from the data: the tension between content area literacy and disciplinary literacy and the tension between disciplinary-based instruction and interdisciplinarity, which permeates the middle school curriculum. Future research should explore how middle school teachers navigate the pedagogical tensions of disciplinary literacy within interdisciplinarity in light of Common Core State Standards and other current policy initiatives.