Cognitive models of Obsessive-Compulsive disorder (OCD) have emphasized inflated responsibility (Salkovskis, 1985), thought-action fusion (Rachman, 1993), and metacognitive beliefs (Wells, 1997; Wells & Matthews, 1994), as factors contributing to disorder. The metacognitive model views responsibility as a by-product of metacognitions that make little additional contribution to OCD, and gives rise to the following hypotheses: (1) responsibility and meta-cognitive beliefs are positively correlated with obsessive-compulsive symptoms, (2) the relationship between responsibility and obsessive-compulsive symptoms is statistically dependent on meta-cognition, (3), metacognitions positively correlate with obsessive-compulsive symptoms independently of responsibility. The results supported each of these hypotheses and exploratory analyses were conducted to find the best unique set of predictors among a range of metacognitive dimensions. Metacognitive beliefs concerning need to control thoughts, thought-action fusion, and negative beliefs about cognitive competence emerged as reliable predictors. An additional contribution was made by thought-event fusion in one equation. The results provide support for the meta-cognitive model. Copyright (C) 2004 John Wiley Sons, Ltd.