The present dissertation focused on the applicability of the Classroom Assessment Scoring System（CLASS）instrument,factors that influence teacher-child interaction,and its relations with child outcomes.The dissertation had three aims: First,it examined the applicability of the CLASS instrument in the Ethiopian preschool context.Also,considered was the level of classroom quality in the domains of Emotional Support,Classroom Organization,and Instructional Support.Second,it investigated teacher-related factors that influence teacher-child interactions.The third aim was to examine the relationship between teacher-child interaction quality and preschoolers’ social and language development.Altogether 26 classrooms and 55 preschool teachers were observed using the CLASS instrument.Other sources of data used in the analyses include assessments of 177 preschoolers’ language development,questionnaires filled out by preschool teachers（n = 55）,and teachers’ ratings of children’s social development.The evidence from confirmatory factor analysis provide support for the applicability of the CLASS in the Ethiopian preschool classrooms.Further,the results indicated that an average level of classroom quality was observed in the emotional support domain while classroom organization and instructional support were each rated at the low end.Statistically significant positive correlations were found between teacher factors（i.e.,teacher belief,self-efficacy,and teaching experience）and teacher-child interaction quality.Moreover,teacher beliefs significantly predicted teachers’ emotional support and classroom organization while teaching experience significantly predicted instructional support.The results also suggest that emotional support,classroom organization,and instructional support were not significantly associated with children’s social and language development.Limitations and future directions,and implications for practice are discussed.