REL Midwest received a request for information on evidence-based research/guidance on how to close achievement gaps in middle schools and high schools. Following an established REL Midwest research protocol, we conducted a search for research reports as well as descriptive and policy-oriented briefs and articles on closing achievement gaps. We focused on identifying resources that specifically addressed high school and middle school gaps. The sources included federally funded organizations, additional research institutions, several educational research databases, and a general Internet search using Google and other search engines. We also searched for other appropriate organizations that may act as resources on this issue. We have not done an evaluation of these organizations or the resources themselves but offer this list for your information only.