Derek Kreager’s research is primarily situated at the intersection of adolescent social development and risk behaviors. His prior studies have focused on school-based friendship networks and adolescent delinquent behaviors. He received a Scholars’ Award from the William T. Grant Foundation to research the associations between adolescent friendships and romantic/sexual involvement. Related research has also been supported by the National Institute of Drug Abuse to study adolescent romantic relationships and substance use in the PROSPER Intervention Study. More recently, he has extended his interests in network dynamics to study peer associations among adult inmates.