Following a large, diverse sample of 4,096 children in 27 schools, this study evaluated the impact of 3 aspects of peer relations, measured concurrently, on subsequent child aggressive-disruptive behavior during early elementary school: peer dislike, reciprocated friends' aggressiveness, and classroom levels of aggressive-disruptive behavior. Teachers rated child aggressive-disruptive behavior in 1st and 3rd grades, and peer relations were assessed during 2nd grade. Results indicated that heightened classroom aggressive-disruptive behavior levels were related to proximal peer relations, including an increased likelihood of having aggressive friends and lower levels of peer dislike of aggressive-disruptive children. Controlling for 1st grade aggressive-disruptive behavior, the three 2nd grade peer experiences each made unique contributions to 3rd grade child aggressive-disruptive behavior. These findings replicate and extend a growing body of research documenting the multifaceted nature of peer influence on aggressive-disruptive behavior in early elementary school. They highlight the importance of the classroom ecology and proximal peer relations in the socialization of aggressive-disruptive behavior.