The two studies presented in this paper investigated the impact of controllable versus uncontrollable stressful life events (SLE) and low versus high thought suppression upon symptoms of obsessive-compulsive disorder (OCD) in both a non-clinical sample (Study 1) and a clinical sample (Study 2). The sample for Study 1 consisted of 269 undergraduate university students and the sample for Study 2 consisted of 91 participants obtained from the Obsessive Compulsive and Anxiety Disorders Foundation of Victoria, Australia. Participants in both studies were given identical questionnaires measuring anxiety, depression, thought suppression, OCD, and, the control, magnitude and number of SLEs suffered during the previous 18 months. In both studies, analysis of covariance (ANCOVA) followed by post hoc tests indicated that high OCD scores were associated with high thought suppression and low perceived control over high magnitude stressful life events relative to controls. The results suggest that high thought suppression coupled with low control over stressful life events may interact with other predisposing factors, such as genetic vulnerability to produce OCD symptoms.