This report examined the nature of obsessive-compulsive disorder (OCD) symptoms nominated for treatment and investigate improvement in OCD symptom dimensions. Youth with OCD (N = 71) participated in a clinical trial that compared exposure-based cognitive behavior therapy (CBT) to psychoeducation plus relaxation training (PRT). Participants completed a baseline assessment to characterize OCD severity. Next, parents and youth collaboratively developed an OCD symptom treatment hierarchy. Afterward, these symptoms were independently reassessed at each session by youth and parents. After 12 sessions, a posttreatment assessment was completed by independent evaluators. A greater incidence of baseline aggressive/checking symptoms predicted a positive CBT treatment response. For parent ratings of youth distress, CBT outperformed PRT across symptom dimensions, but hoarding symptoms exhibited a slower rate of improvement relative to other dimensions across treatments. For youth distress ratings, CBT outperformed PRT across most symptom dimensions. Although symmetry/ordering symptoms exhibited a slower rate of improvement relative to other dimensions across treatments, post hoc tests found no difference in the average distress rating for symmetry/ordering symptoms between treatment groups. Finally, across symptom dimensions, parents reported a linear reduction in youth distress, whereas youth experienced a nonlinear reduction in distress that diminished over treatment. Exposure-based CBT is beneficial for OCD symptoms and remains the principle treatment for pediatric OCD. However, as symmetry/ordering symptoms exhibited improvement from CBT and PRT, there is some shared treatment mechanisms that improves these symptoms. Finally, as youth perceive diminishing distress reduction over time, clinicians are encouraged to employ appropriate reinforcement strategies in treatment.