Anxiety commonly co-occurs in children with autism spectrum disorder (ASD) and contributes to the difficulties students experience at school. Few school-based interventions demonstrate strong empirical data for successfully treating anxiety in children with ASD at school. The factors that are important to maximizing school-based intervention outcomes are not well studied in this population. The present study examined the effectiveness of a modified version of the "Brief Coping Cat," a cognitive behavioral therapy (CBT) intervention with three students identified with ASD and anxiety. Using a multiple-baseline design, students participated in an 8-week intervention designed to teach them how to recognize signs of anxious arousal and use learned strategies to manage the symptoms at school. The intervention was delivered in the classroom with direct and intentional teacher involvement. Intervention outcomes were measured with student self-reported weekly ratings of anxiety and teacher observational data, and moderate effects were found. Implications for the delivery of anxiety interventions in a flexible format at school for youth with autism spectrum disorder (ASD) are discussed.