Background Research supports the efficacy of intensive cognitive behavioral therapy (CBT) for the treatment of adolescent panic disorder with or without agoraphobia (PDA). However, little is known about the conditions under which intensive treatment is most effective. The current investigation examined the moderating roles of baseline fear and avoidance in the intensive treatment of adolescent PDA. Methods Adolescents with PDA (ages 11–17; N = 54) were randomized to either an intensive CBT treatment (n = 37) or a waitlist control condition (n = 17). PDA diagnosis, symptom severity, and number of feared and avoided situations were assessed at baseline and 6‐week posttreatment/postwaitlist. Hierarchical regression analyses examined the relative contributions of treatment condition, number of baseline feared or avoided situations, and their interactions in the prediction of posttreatment/waitlist PDA symptoms. Results The main effect of intensive CBT on posttreatment PDA symptoms was not uniform across participants, with larger treatment effects found among participants with lower, relative to higher, baseline levels of fear and avoidance. Conclusions Findings help clarify which adolescents suffering with PDA may benefit most from an intensive treatment format.