<p>This study examined whether childhood trauma was associated with obsessive–compulsive symptom severity in adults diagnosed with obsessive–compulsive disorder, with dissociative experiences and world assumptions specified as parallel statistical mediators. Data were collected from adults with a clinical diagnosis of obsessive–compulsive disorder who completed standardized measures of childhood trauma, dissociation, world assumptions, and obsessive–compulsive symptoms. The findings showed that higher childhood trauma scores were associated with greater obsessive–compulsive symptom severity. This association was partially represented in the model by higher dissociative experiences and lower world-assumption scores, reflecting less positive world assumptions. The results were consistent with an associative parallel mediation model in which dissociative experiences and world assumptions were modeled as statistical mediators of the relationship between childhood trauma and obsessive–compulsive symptoms. These findings highlight the clinical relevance of assessing trauma history, dissociative tendencies, and world assumptions in individuals with obsessive–compulsive symptoms. Given the cross-sectional design, the findings should be interpreted as associative rather than causal.</p>