This brief by Development and Research in Early Mathematics Education (DREAM) examined two districtwide efforts to improve elementary mathematics instruction. Their analysis found that coaches’ effectiveness is linked to how their district interacts and fits its coaching program into its instructional improvement infrastructure. The brief focuses on four infrastructure dimensions that impact coaches’ effectiveness: specificity, inclusivity, authority, and alignment. These dimensions shape who coaches interact with, how coaches are able to share their district’s vision, and the nature of their work. Of the two districts examined, one had stronger infrastructure to support its coaches. The brief outlines the context of how this district’s infrastructure shaped its coaches’ practices, provides examples of how each of the four dimensions appeared in the district, and describes the way each dimension impacted coaches. Overall, this policy brief can serve as a guide for district leaders, such as superintendents, looking to evaluate or redesign how their infrastructure supports the work of coaches.