Objective: The Strengths and Difficulties Questionnaire is a 25-item instrument developed to assess emotional and behavioral problems. The current study attempted to replicate previous European structural analyses and to describe the latent dimensions that underlie responses to the parent-reported version of the Strengths and Difficulties Questionnaire for a representative sample of U.S. children and adolescents. Method: Parents/guardians of a national probability sample of 9,574 children and adolescents 4 to 17 years of age were administered the Strengths and Difficulties Questionnaire to assess emotional and behavioral problems within the past 1 month. A principal components analysis was performed for replication purposes, and exploratory and confirmatory factor analyses were performed to extract the underlying factors. Results: The predicted five-component structure (emotional, hyperactivity, prosocial, peer, conduct) was not entirely confirmed. Some items intended to assess conduct problems were more closely related to hyperactivity, and some items intended to assess peer problems were more strongly correlated with emotional or prosocial problems. Factor analyses revealed a stable three-factor model consisting of externalization problems, internalization problems, and a positive construal factor. Conclusions: The current analyses suggest that U.S. parents may construe conduct problems and peer problems differently than do European parents. These cultural differences may affect the assessment of psychopathology for children. J. Am. Acad. Child Adolesc. Psychiatry, 2004;43(9):1159-1167. Key Words: questionnaire, reliability, psychopathology, factor structure.