This study investigated how a high school literacy coach provided coaching to support teachers' understanding and implementation of disciplinary literacy instruction. With a focus on collaborations between the literacy coach and teachers in the disciplines of social studies, math, and English, this article presents three case studies that illustrate how the coach and teachers designed instruction within and beyond the district's curricular frameworks. Findings suggest when the coach situated herself as a collaborator, rather than an expert, and positioned the teacher as the disciplinary expert, the coach and teacher were able to foreground the discipline and plan meaningful disciplinary literacy instruction. The use of open-ended questions, think-alouds, and an examination of instructional tasks from students' perspectives enabled the teachers to strengthen their disciplinary literacy instruction.