Systematic direct observations (SDOs) and behavior rating scales are integral to multimethod behavioral assessment approaches. The present study investigated the convergent validity of the Behavior Observation of Students in Schools (BOSS) form, a widely utilized SDO system, with the most frequently used teacher rating scales in schools, the Behavioral Assessment System for Children, Third Edition (BASC-3) and the Behavioral and Emotional Screening System, third edition (BESS-3). Specifically, the present study compared independent observer data collection of student on-task and disruptive behaviors on the BOSS with teachers' ratings of behavioral problems on the BASC-3 and BESS-3. Data come from a sample of 136 teachers and 349 students with or at risk of disruptive behavior disorders (DBDs). Pearson correlations were computed between BOSS and teacher ratings on the BASC-3 and BESS-3. Findings demonstrated significant, small to moderate correlations. Results indicate evidence of convergent validity for the BOSS and BASC3 assessments and highlight multimethod behavioral assessment's utility in supporting students with or at risk of DBDs.