The authors examined the utility of a modified version of the "Systematic Screening for Behavior Disorders" for use at the high school level to address issues of comorbidity. Results suggested that the modified version was able to discriminate among students with varying degrees of risk in terms of academic performance as measured by GPA. In terms of convergent validity, teachers were able to differentiate between the social skills of students rated with typical behaviors and those at risk for externalizing or comorbid behaviors in terms of cooperation, self-control, school adjustment, and empathy skills. Furthermore, teachers were better able to discriminate externalizing behaviors relative to internalizing behaviors. Overall, solely relying on teacher nominations may be sufficient for discriminating between the presence versus absence of risk. However, it may not be sufficient to discriminate among the presence of different types of risk, particularly internalizing behaviors. Limitations and educational implications are discussed. (Contains 4 tables.)