This study examined the factor structure of the parent and teacher versions of the Strengths and Difficulties Questionnaire (SDQ; R. Goodman, 1997) with a sample of first-grade children at risk for educational failure. The 5-factor model previously found in studies using exploratory factor analysis was fit to the data for both parent and teacher questionnaires. Fit indices for both versions were marginally adequate. Model fit was comparable across gender and ethnic groups. Factor fit for the parent questionnaire was invariant across parent educational level. The examination of convergent and discriminant validity included peer evaluations of each SDQ construct. Thus, each of the five constructs was evaluated by three sources (parent, teacher, and child). On the basis of D. T. Campbell and D. W. Fiske's (1959) multitrait-multimethod approach as well as a confirmatory factor analysis using the correlated uniqueness model, the SDQ has good convergent validity but relatively poor discriminant validity.