The ways in which teachers perceive and subsequently respond to preschoolers' behavior have significant implications for children's experience in the classroom. To further understand the nature and variability of teacher perception of young children's behavior, this study examined how teachers characterized the disruptive behaviors of a large and diverse sample of preschoolers (N = 2,427) at the beginning of the school year. Descriptive analyses provide extensive information regarding the frequency, severity, and comorbidity with which teachers reported preschoolers to display hyperactivity, inattention, and oppositionality in the classroom. Further, multilevel regression models allowed for examination of the association between perception of disruptive behavior and teachers' demographic, professional background, and belief characteristics. Research Findings: Findings provide a current understanding of the salience of classroom disruptive behavior as seen through the eyes of the preschool teacher and indicate a nuanced relationship between this perception and teacher characteristics. Specifically, findings highlight teacher race/ethnicity, behavioral attribution beliefs, and self-efficacy to be uniquely associated with perception of preschoolers' various behavior problems. Practice or Policy: Implications for teacher training and school-based intervention are discussed. (author abstract)