The metacognitive model of obsessive-compulsive symptoms [Wells, A. (1997). Cognitive therapy of anxiety disorders: a practice manual and conceptual guide. Chichester, UK: Wiley] emphasizes three types of metacognitive knowledge in the etiology and maintenance of symptoms: thought fusion beliefs, beliefs about the need to perform rituals, and criteria that signal rituals can be stopped. We tested the model using a series of hierarchical regression analyses. Results showed that each metacognitive domain when entered in their hypothesized causal sequence explained incremental variance in two different measures of obsessive-compulsive symptoms, with worry controlled. These incremental relationships remained when non-metacognitive beliefs (e.g., responsibility and perfectionism) which have been linked to obsessive-compulsive symptoms in other theories were controlled. Results provide further support for the metacognitive model.