Behavior rating scales are frequently used to assess social-emotional behaviors of children. While broadband behavior rating scales often measure similarly named constructs, it is unclear how consistently different instruments measure those constructs. Head Start teachers completed the preschool versions of the Behavior Assessment System for Children-3 (Reynolds and Kamphaus 2015) and the Caregiver-Teacher Report Form (Achenbach and Rescorla 2000) at the same point in time on a sample of 56 children with social-emotional concerns. The consistency of results was evaluated through correlations, mean scores, and classification consistency. The two instruments were generally consistent at measuring externalizing behavioral constructs but not internalizing ones. The results imply that much caution is needed in the use of teacher behavior rating scales when assessing internalizing behaviors at the preschool level. (author abstract)