The cognitive model of obsessive-compulsive disorder (OCD) posits that dysfunctional cognitive beliefs are crucial to the onset and maintenance of OCD; however, the relationship between these cognitive beliefs and the heterogeneity of OCD symptoms in children and adolescents remains unknown. We examined how the major belief domains of the cognitive model (inflated responsibility/threat estimation, perfectionism/intolerance of uncertainty, importance/control of thoughts) and dysfunctional metacognitions were related to OCD symptoms across the following dimensions: doubting/checking, obsessing, hoarding, washing, ordering, and neutralization. Self-report ratings from 137 treatment-seeking youth with OCD were analyzed. When cognitive beliefs and symptom dimensions were analyzed in tandem, inflated responsibility/threat estimation and dysfunctional metacognitions were uniquely related to doubting/checking, obsessing, and hoarding and perfectionism/intolerance of uncertainty to ordering. Cognitive beliefs explained a large proportion of variation in doubting/checking (61%) and obsessing (46%), but much less so in ordering (15%), hoarding (14%), neutralization (8%), and washing (3%). Similar relations between cognitive beliefs and symptom dimensions were present in children and adolescents. Cognitive beliefs appear to be relevant for pediatric OCD related to harm, responsibility, and checking, but they do not map clearly onto contamination and symmetry-related symptoms. Implications for OCD etiology and treatment are discussed.