This study investigated the cross-informant agreement among student self-report, teacher report, and parent report on the Strengths and Difficulties Questionnaire translated into Finnish (SDQ-Fin) and estimated mean convergent and divergent correlations with a sample of fifth-grade Finnish students (N = 588) and the cross-informant agreement among student-teacher-parent informants separately for those with and without special education support. In addition, the study estimated the within-rater stabilities of SDQ subscales for students with and without special education support between two measurements at a one year interval. The cross-informant agreement on SDQ-Fin subscales was moderate with cross-informant correlations ranging from 0.12 to 0.42. The cross-informant agreement between teachers and students was in general higher for students with special education (SE) support than students without special education (NSE) support. The mean convergent correlations were higher than the mean divergent correlations across raters. The rater stabilities of SDQ subscales for NSE students and SE students between fifth and sixth grade as indicated by stability correlations were all statistically significant. Our findings provide additional evidence of the usefulness of the SDQ in school environments, and underline the importance of a multi-informant approach to the evaluation of emotional and behavioral problems.