School improvement is complex and difficult, especially in comprehensive support and improvement (CSI) schools, which concurrently struggle with multiple challenges. To guide state education agencies (SEAs) in supporting schools, this report summarizes the resources that SEAs have identified and developed, insights from national technical assistance (TA) providers, and effective practices highlighted in the research literature to form a national picture of state supports for evidence-based comprehensive school reform. A separate annex, "Profiles of State Supports for Evidence-Based Whole School Improvement," contains more detailed information about the approaches taken by each state and the District of Columbia. The aim of this guide is to enable SEAs, faced with increasing responsibility and decreasing resources, to improve their supports for schools undergoing comprehensive reform. SEA leaders can compare their own school improvement efforts with those of other SEAs and national trends to identify any current gaps in their supports -- and garner ideas on how to enhance their supports. SEA leaders can also use this report to identify extant resources, reducing the need to reinvent the wheel. This report will also be useful to organizations that support SEAs, such as TA providers, to identify where their support is most needed.