Responding to complex problems and emergencies such as COVID-19 requires both rapid response and long-term planning. Part of the response and planning needs to be based on lessons learned from previous crisis experiences. Organizations should be routinely conducting strategic reviews of previous responses, projects, or events to analyze the implementation and effect of actions, document lessons learned, and apply those lessons in new conditions. Regional Comprehensive Centers can assist state education agencies (SEAs) or local education agencies (LEAs) in reviewing actions, identifying the lessons learned, and applying the lessons to continually improve student outcomes. An After-Action Review is a method for conducting such reviews. An After-Action Review (AAR) is a method for extracting lessons from one action, event, or project, and applying the lessons learned to others. It enables a team to analyze for themselves what happened, why it happened, and how to use learnings to sustain strengths and improve weaknesses. This guide provides an overview of the AAR, common AAR questions and answers, types of AARs, reasons to conduct AARs, information on planning an AAR, conducting an AAR, and how to use the results of the AAR. An After-Action Planning Checklist, After-Action Review Ground Rules, After-Action Review Key Questions, After-Action Review Template, and 5 Whys Worksheet are also included.