The Importance of Metacognitions in the Understanding and Treatment of Obsessive Compulsive Disorder The present article discusses three cognitive approaches of Obsessive Compulsive Disorder (OCD): (1) Beck's theory of content-specificity, (2) Salkovskis' cognitive-behavioural approach and (3) Wells' more recent theory of metacognitions. Wells' approach is explained in more detail: the so called Self-Regulatory Executive Function model is presented as well as special aspects of thinking in OCD, for example the self-referential status of thinking, thinking in object mode and aspects of `thought-action fusion'. The relevance of Wells' metacognitive approach for the development and the maintenance of OCD is discussed. Furthermore, proposals are made on how to include these issues in the psychotherapy of OCD.