A Dutch translation of the Strengths and Difficulties Questionnaire (SDQ) was made. In the first wave of data collection, self-report data of 11- to 16-yearolds (N = 970) were collected on the SDQ and other measures of psychopathology. In the second wave of data collection, extended versions of the SDQ were completed by 11- to 16-year-olds (N = 268), by parents of 8- to 16-year-olds (N = 300) and by teachers of 8- to 12-year-olds (N = 208); in addition, the Child Behaviour Checklist (CBCL) was completed by the parents and the Youth Self Report (YSR) by the 11- to 16-year-olds. The results reveal that the internal consistency of the teacher SDQ is good; and the parent and self-report SDQ are generally acceptable and comparable with the internal consistencies of CBCL/YSR. The mean inter-informant product-moment correlations of the SDQ scales were satisfactory (parent-teacher 0.38; teacher-self-report 0.27; parent-self-report 0.35) and comparable with the mean inter-informant correlations of the CBCL and YSR (0.34). The inter-informant rank correlations of the impact questions were also satisfactory (mean parent-teacher 0.48; mean parent-self-report 0.24). Concurrent validity with the other measures of psychopathology used in the present study was good.