Objective: This pilot randomized controlled trial examined the acceptability and feasibility of a cognitive-behavioral therapy (CBT) intervention for children with ADHD and anxiety, and provided preliminary information on child and family outcomes. Method: Children with ADHD and anxiety (8-12 years) were randomized to receive an adapted version of the Cool Kids CBT program or usual clinical care. Key outcomes included feasibility and acceptability of the intervention (participant enrollment, drop-out, intervention session attendance), remission of anxiety assessed via diagnostic interview, ADHD symptom severity, quality of life (QoL), and parent mental health. Results: Twelve children participated (67% uptake). Most families attended all 10 intervention sessions, with no drop-outs. Intervention participants had marked improvements in both child and family well-being by parent and teacher report, including anxiety, ADHD symptom severity, QoL, and parent mental health. Conclusion: Non-pharmacological interventions may improve important domains of functioning for children with ADHD and anxiety, including ADHD symptom severity.