Knowledge plays an inarguably critical role in reading comprehension. When considering the science of reading, it is important to engage with varying theoretical frameworks and empirical research that inform our collective understanding regarding the intersection of knowledge and literacy in K–12 classrooms. Therefore, the purpose of this article is to consider sociocultural and cognitivist perspectives on the role that knowledge plays throughout the reading process and to examine whose knowledge matters. Then, the authors address three tensions related to the role of knowledge in K–12 literacy instruction and offer research‐based perspectives on how educators, researchers, school leaders, parents, and community leaders can rethink knowledge to support students in learning from texts. First, the authors reframe the knowledge gap and suggest ways that teachers can privilege students’ knowledge as assets during literacy instruction. Second, the authors address the importance of supporting students in activating, integrating, and revising their knowledge during text processing and suggest evidence‐based instructional techniques that support students’ learning from texts. Finally, the authors contend that content knowledge is not the only type of knowledge that matters in reading and suggest how teachers can support readers in using other types of knowledge that are crucial to comprehension.