This article provides an analysis of the current knowledge base of social skills training (SST) with students with, or at risk for, Emotional and Behavioral Disorders (EBD). This knowledge base is evaluated with respect to issues regarding construct, internal, external, and social validity of the SST literature. Research syntheses investigating construct validity suggest that the three domains of social interaction, prosocial behavior, and social-cognitive skills adequately represent the social skills construct. Internal validity analyses based on the results of six meta-analyses suggested that SST is an effective intervention strategy for students with EBD, showing a 64% improvement rate relative to controls using the Binomial Effect Size Display. External validity analyses showed that SST is effective across a broad range of behavioral difficulties, such as aggression externalizing behaviors, internalizing behaviors, and antisocial behavior patterns. Some weaknesses were noted in the social validity of SST outcome measures, and recommendations are made for improvement in this area. Overall, SST is an effective and essential part of a comprehensive intervention program for students with EBD. (Contains 1 table.)