BACKGROUND: Improved understanding of the cognitive and behavioural processes underpinning panic disorder (PD) in adolescents could improve identification and treatment. AIMS: We investigated whether the processes outlined in Clark's (1986) cognitive model of PD are observed in adolescents with PD, are specific to PD, and predict symptom severity. METHOD: We recruited three groups of adolescents (12-17 years): 34 with a PD diagnosis, 33 with another anxiety disorder excluding PD ('clinical control'), and 34 scoring below the clinical cut-off on a measure of anxiety symptoms ('community control'). Participants self-reported on measures of PD symptom severity, catastrophic cognitions, bodily sensation fear, and safety-seeking behaviours. RESULTS: The PD group reported significantly higher levels of catastrophic cognitions and safety-seeking behaviours than both control groups. They reported significantly higher levels of bodily sensation fear compared with the community but not the clinical control group. All process measures positively predicted PD symptom severity across all groups. CONCLUSIONS: We found evidence of catastrophic cognitions and safety-seeking behaviours as PD-specific processes in adolescents which predict symptom severity. Bodily sensation fear also predicted symptom severity. Findings support Clark's cognitive model of PD in adolescents and suggest that catastrophic cognitions and safety behaviours may be targets for adolescent PD treatment.