Premenstrual dysphoric disorder (PMDD) is a psychiatric disorder that causes serious impairments in the functioning and quality of life of affected women. Until recently, research efforts were somewhat hampered by the lack of formal diagnostic criteria, which have now been codified as a category in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). Better characterization of deficits in socioemotional functioning caused by PMDD may aid in improving treatment efforts. In this investigation, prospective symptom ratings, based on DSM-5 criteria, were used to measure PMDD symptoms in 36 women (18 with PMDD and 18 healthy controls). Two self-report inventories, the Emotion Regulation Questionnaire and the Difficulties in Emotion Regulation Scale, were used to measure ability to regulate emotions, and socioemotional functioning was measured by inventories of social connectedness, perceived stress, and affect. Potential relationships between ability to regulate emotion and PMDD symptom severity, as well as other measures of socioemotional functioning and affective state, were tested. Women with PMDD reported significantly more behavioral impulsivity and greater difficulties in regulating emotion and in socioemotional functioning. Cognitive or behavioral strategies to improve these problems may benefit women with PMDD and help to alleviate distress caused by this disorder.