This document analyzes the psychometric properties of the Swedish version of the Strengths and Difficulties Questionnaire (SDQ) among children and adolescents ages 12-16. It examines the internal consistency, factor structure, and validity of the SDQ using data from community and service contact samples. The results show good internal consistency for most scales. Factor analyses support a bifactor model over the original 5-factor model. Validity analyses find the Emotional Problems scale best distinguishes the samples, while other scales have lower accuracy. Further analyses are suggested to improve understanding of the SDQ's performance in Swedish populations.