Interest in social and emotional learning (SEL) skills is growing rapidly with all 50 states adopting SEL standards for preschool children. However, data on these type of skills for young children are limited due to a paucity of psychometrically-sound assessments. Further, most available assessments are lengthy and minimally aligned with widely used SEL frameworks such as the model proposed by the Collaborative for Academic, Social, and Emotional Learning (CASEL). Thus, the current study focused on the development of valid and time-efficient rating scales of young children’s SEL skills using teachers and parents as informants. We used item response theory to select items from the SSIS Social Emotional Learning Edition (SSIS SEL; Gresham & Elliott, 2017) using the national standardization sample of the measure. We then examined initial evidence of score reliability, validity, and fairness for the SSIS SEL Brief Scales – Preschool Forms resulting from this process. Results provide initial evidence for score reliability, validity, and fairness for both the Teacher and Parent versions of this measure. (author abstract)