Just as teachers' perceptions of instructional materials influence what they do with those materials, school leaders' perceptions of instructional materials influence their decisions about how and how strongly to support teachers' material use. The authors address a gap in existing literature by identifying what school leaders regard as key dimensions of quality instructional materials and describing the role that school leaders play in guiding the selection and use of instructional materials. The authors found that school leaders particularly valued characteristics of instructional materials that facilitated teachers' implementation and use of the materials. They also prioritized standards-aligned materials, perceiving these as best meeting the needs of their teachers and students. Fewer school leaders identified cultural relevance, language-acquisition supports, and social-emotional learning supports as essential dimensions of quality instructional materials. School leaders influence teachers' use of instructional materials by involving teachers in the selection of instructional materials, creating buy-in for district-recommended or -required curriculum, and providing guidance that balanced teacher autonomy and the fidelity of curriculum implementation. During the coronavirus disease 2019 (COVID-19) pandemic, school leaders grew more concerned about the engagement and social-emotional learning supports that materials offered. These findings can provide useful guidance to district policymakers about how to leverage the role of school leaders in the use of instructional materials and what might support school leaders in helping teachers use their materials thoughtfully.