This study explored whether variability in emotion regulation was associated with several clinical correlates of OCD and an attenuated response to treatment. Participants in this study were 137 youth (and their parents) aged 7–17 years with a primary diagnosis of OCD. Parents completed study questionnaires and children received intensive CBT with exposure and response prevention treatment. A median split of responses to the baseline Emotional Control (EC) index of the BRIEF, resulted in two groups of children – those with relatively greater and poorer EC. The results indicated that children in the relatively poorer EC group had significantly greater OCD severity, more family accommodation, internalising and externalising symptoms. They were also more likely to have a comorbid diagnosis of oppositional defiant disorder or social phobia. Additionally, children with relatively greater EC were more likely to have attained response or remission of their symptoms immediately following treatment. Similarly, at three months following treatment there were fewer responders to treatment among the lower EC group relative to the higher EC group; however, there was no significant difference for treatment remission between groups. Therefore, EC may be an indicator for a more severe presentation of OCD and a poorer response to treatment.