Borderline Personality Disorder (BPD) is characterized by unstable mood states, chaotic interpersonal relationships, and behavioral dysregulation in the form of selfinjurious acts that results in notable functional impairment. Emotion dysregulation, marked by strong shifts in emotional states away from baseline levels across subjective and physiological substrates, is believed to reflect one mechanism in the relationship between BPD and functional impairment. However, it remains unclear whether emotion dysregulation represents a general tendency to experience both positive and negative emotions keenly, or to specifically be sensitized to negative mood states. The present study examined the relationship between BPD symptoms and emotion dysregulation across neutral, negative, and positive valenced emotional states in a sample of twenty-two community dwelling adults with histories of psychiatric disorders. Emotion dysregulation was measured via subjective affect ratings and pupillary responses that index sympathetic nervous system reactivity when participants recalled neutral, stressful, and pleasant events that occurred during the prior 3 months. Results and clinical implications are discussed.