Obsessive-compulsive disorder (OCD) is a condition marked by recurrent and distressing thoughts, images, and urges accompanied by repetitive physical or mental rituals. An emerging line of work suggests that emotion may be an important consideration when looking at the role of impulsivity across the spectrum of psychopathology, including OCD. The current study examined the relationship between obsessive-compulsive symptomatology (OCS) and impulsive cognitive and behavioural reactions to emotion using a multi-study, multi-method approach. Data were collected cross-sectionally online (Study 1) or via an in-person laboratory visit (Study 2). In Study 1, self-report measures of impulsivity and OCS were administered to a large, non-selected community sample (N=386). Study 2 extended these findings with a young adult sample (N=107) with clinically elevated OCS using self-report measures, clinical interview, and two behavioural symptom provocation tasks. Emotion-related impulsivity, but not non-emotion-related impulsivity, was associated with greater severity of OCS across symptom domains and across all modes of assessment. Impulsive cognitive responses to emotion were associated with greater obsession severity, while impulsive behavioural reactions to emotion were associated with greater compulsions. Emotion-related impulsivity also acted synergistically with a belief in the importance and control of thoughts, such that this established risk factor for OCD was associated with greater OCS severity only when behavioural reactivity to emotion was also present. Results highlight the importance of considering emotional context when studying impulsivity in OCD, and point to the potentially differential relationship between OCS and behavioural versus cognitive impulsive reactions to emotion. Emotion-related impulsivity (ERI) reflects a tendency to act impulsively in the context of strong emotions. ERI was associated with greater OCS across symptom domains and type of symptom assessment (self-report, interview, or symptom provocation). ERI also interacted with an established OCS risk factor, a belief in the importance and control of thoughts, to predict symptom severity, suggesting that it may be important to evaluate and address ERI alongside unhelpful beliefs in patients with OCS. Given the present study's cross-sectional nature, we cannot draw conclusions about the directionality of the ERI - OCS relationship, and while our study included individuals with clinically elevated OCS, results should be replicated in a fully clinical sample.