Although peer influences are thought to be critically important to adolescent development, there is a paucity of research investigating the emotion socialization practices that take place between adolescents. This longitudinal study evaluated close friends' responses to negative emotion using a newly developed assessment tool of peer emotion socialization, you and your friends. Adolescent participants (N = 205) exhibiting a range of internalizing and externalizing problems between 11 and 17 years of age were assessed and re-evaluated two years later. Participants were asked to rate the frequency with which their friends responded to them by encouraging, distracting, matching, ignoring, overtly victimizing, and/or relationally victimizing their emotions. The results indicated high levels of internal consistency and moderate levels of long-term stability. Close friends most often responded supportively to the participants' emotional displays, but these responses differed by gender. Also, friends' emotion socialization responses were concurrently and predictively associated with participant problem status. This study contributes to a better understanding of the processes by which adolescents' emotions are socialized by their friends and has important implications for future prevention and intervention efforts. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.