Metacognitive Theory, amongst other theories, gives an important role to beliefs about mental states, including emotions, in the maintenance of distress. Beliefs about emotions have been most frequently discussed in relation to emotion regulation, and the disorder most associated with problems regulating emotions is borderline personality disorder (BPD). Several theories, namely Mentalization Theory and Biosocial Theory as well as the Emotion Focused Therapy literature specify particular beliefs which are thought to be related to emotion dysregulation. Although several scales exist to measure metacognitions and some specific beliefs about emotions, no comprehensive measure of beliefs about emotions exists. Such a measure would have particular relevance to emotion dysregulation and be useful for developing theory and treatment for BPD. The current study aimed to develop a scale to measure beliefs about emotions and test the relationship of the new measure to various aspects of emotion regulation.