The present study examined predictors of discrepancies between mothers', fathers', and teachers' ratings of 3-year-old children's hyperactivity, attention problems, and aggression. Participants were families of 196 3-year-old children who took part in child and family assessments. Ethnicity was one of the most consistent predictors of discrepancies. African American mothers and fathers were more likely to rate their children's hyperactivity, attention problems, and aggression lower than teachers. In contrast, Latina mothers were more likely to rate their children as more hyperactive and inattentive than teachers. ADHD/ODD diagnoses, parental depression, number of children, and children's pre-academic skills were also predictive of discrepancies for some measures for some informants. These findings provide insight into factors that may contribute to informant discrepancies in ratings of preschool children. (author abstract)