RAND researchers explore the messages teachers receive about what to teach and how to teach English language arts and mathematics in kindergarten through grade 12 schools in the United States, as well as teachers' overall perceptions of coherence and incoherence in instructional systems and how they navigate such systems. The authors conceive of instructional system coherence as the extent to which multiple key system components (e.g., curricula, professional development, summative assessments) related to teaching and learning provide the same signals and supports to teachers and leaders about what instruction should look like. Incoherence occurs when one or more components is not linked to other messages within the larger instructional system or provides conflicting signals to teachers about what instruction should look like. The findings from this interview-based study have implications for policy and practice. The study findings point to practices that school and district leaders might adopt to achieve greater system coherence and support teachers in making sense of the myriad policy messages they receive. In addition, the findings can help state- and district-level leaders reflect on how teachers are positioned to enact equitable instruction. Understanding how teachers are processing messaging around equity and diversity will support schools and districts in implementing effective policy around these goals.