Teachers' ratings of children's competencies may in part reflect characteristics and perspectives of teachers who assigned the ratings, which compromises their validity as a measure of child attributes. The purposes of this study were to use multilevel modeling to (a) estimate between-rater variance in teachers' ratings of children's social behaviors and relationships with teachers and (b) examine characteristics of teachers and classrooms associated with teachers' perceptions of these social competencies. Ratings of 711 children completed by 210 prekindergarten teachers indicated that between 15% and 33% of the total variance in teachers' ratings was attributed to mean differences between raters. After controlling for characteristics of children and their families, teachers' ratings of positive relationships and behaviors were associated with fewer years of experience, higher self-efficacy, non-White race/ethnicity, shorter length programs, better child-teacher ratios, and programs located within school settings. Implications are discussed for interpreting and analyzing teachers' ratings of children's competencies. (Contains 3 tables.)