Objective: The purpose of this research was adaptation and finding psychometric properties of Child Behavior Checklist (CBCL), Youth Self-report (YSR), and Teacher’s Report Forms (TRF) for Farsi-speaking children. Method: The forms were completed for 1437 (748 boys and 689 girls) students in Tehran by their parents, teachers, and by the students. The sample was selected by means of multistage stratified random method Classical test theory was used to estimate psychometric properties of items and scales of the forms. Internal consistency of each scale was obtained by using Cronbach alpha for each gender and age group. Results: Ranges of these coefficients were .63 to .95. To examine stability of the forms, 134 subjects were selected randomly from the normative sample and the forms were completed for them with an interval of 5 to 8 weeks. Cross-informant agreement was examine. Ranges of these coefficients were .09 to .67. Content, criterion and construct validity of the forms were studied by appropriate methods, including inter-correlation of scales, item-total correlation, group discrimination, discrimination power, and factor analysis. Conclusion: The results showed that reliability and validity of all three forms were high and they could be used to assess emotional and behavioural problems of children aged 6 - 18 years.