<p>Teacher perceptions have been conceptualized as a critical interpersonal mechanism mediating the effects of classroom interactions on student learning. However, several questions remain regarding the differential impact of ability and engagement perceptions, how their association with reading achievement unfolds, and whether they differ between distinct teacher groups, particularly within the context of intervention programs. This study examined how classroom- and support-teacher perceptions were associated with reading speed, the distinctiveness of ability and engagement perceptions, and differences between classroom and support teachers. Two hundred and eighty second-grade students with reading difficulties enrolled in the A to Z intervention program were followed across one school year using longitudinal cross-lagged models. Classroom teachers rated students’ reading ability and engagement, while support teachers rated their engagement. For classroom teachers, the results revealed reciprocal links: reading speed predicted perceptions of reading ability and engagement, and perceptions of ability in turn predicted subsequent reading speed. The results also showed reciprocal associations for support teachers. However, these were less stable and more context-dependent. Reading speed predicted engagement perceptions only early in the year, whereas engagement perceptions predicted later reading speed. These findings highlight teacher perceptions as responsive to and predictive of students’ reading speed, with distinct patterns according to the teacher role and instructional context.</p>