This guide is intended to help elementary school educators as well as school and district administrators develop and implement effective prevention and intervention strategies that promote positive student behavior. The guide includes five recommendations and indicates the quality of the evidence that supports them: (1) Identify the specifics of the problem behavior and the conditions that prompt and reinforce it; (2) Modify the classroom learning environment to decrease problem behavior; (3) Teach and reinforce new skills to increase appropriate behavior and preserve a positive classroom climate; (4) Draw on relationships with professional colleagues and students' families for continued guidance and support; and (5) Assess whether schoolwide behavior problems warrant adopting schoolwide strategies or programs and, if so, implement ones shown to reduce negative and foster positive interactions. Suggested strategies for carrying our each recommendation are included, identifying potential roadblocks to implementation that may be encountered and possible circumventions. Technical details about the studies that support the recommendations are provided. Four appendixes are included: (1) Postscript from the Institute of Education Sciences; (2) About the Authors; (3) Disclosure of Potential Conflicts of Interest; and (4) Technical Information on the Studies. (Contains 79 footnotes and 4 tables.) [This report was prepared for the National Center for Education Evaluation and Regional Assistance, Institute of Education Sciences by the What Works Clearinghouse, which is operated by Mathematica Policy Research, Inc.]