Emotion regulation is a topic of great interest due to its relevance to navigating everyday life, as well as its relevance to psychopathology. Recent research indicates that beliefs about the automaticity of mood regulation are critical to psychological health. In the present study we assessed beliefs about the automaticity of positive mood regulation in relationship to self-reported mood symptoms and explicit emotion regulation strategies. Participants (n = 200) completed an online survey including a scale assessing beliefs about automatic downregulation of positive emotions (i.e. BAMR-PED), beliefs about automatic mood regulation for negative emotions, mood symptoms, and emotion regulation strategies. Results suggested that beliefs about automatic positive emotion regulation were associated with unhelpful emotion regulation strategies and reduced negative affect as well as fewer depressive, manic, and anxiety symptoms. Test-retest of the novel BAMR-PED measure was tested with a further sample (n = 46) and found to be acceptable. Future research should explore how these automatic beliefs have relevance to clinical disorders characterised by positive emotion disturbance, such as bipolar disorder.