Abstract The purpose of this investigation was to examine correlates of parent, child, and therapist treatment expectations and their role in the exposure-based treatment of childhood obsessive compulsive disorder (OCD). Treatment expectations were assessed among 49 youth with primary OCD, their parents, and therapists as part of the baseline evaluation and post-treatment clinical outcomes were determined by blind evaluators. Baseline depressive symptoms, child/parent-rated functional impairment, externalizing behavior problems, number of comorbid psychiatric disorders, and a lower perception of control were associated with lower pre-treatment expectations. Parent expectation was associated with parental OCD symptoms, child depressive symptoms and child-reported impairment. Therapist expectations inversely correlated with child depressive symptoms, externalizing problems, and child-rated impairment. Pre-treatment OCD severity and prior treatment history were not linked to expectancy. Finally, higher treatment expectations were linked to better treatment response, lower attrition, better homework compliance, and reduced impairment.