--- - |2+ Background Because emotional symptoms are common in attention‐deficit/hyperactivity disorder (ADHD) patients and associate with much morbidity, some consider it to be a core feature rather than an associated trait. Others argue that emotional symptoms are too nonspecific for use as diagnostic criteria. This debate has been difficult to resolve due, in part, to the many terms used to describe emotional symptoms in ADHD and to concerns about overlap with mood disorders. Methods We sought to clarify the nature of emotional symptoms in ADHD by reviewing conceptual and measurement issues and by examining the evidence base regarding specificity of such symptoms for ADHD. We reviewed the various terms used to define emotional symptoms in ADHD, clarify how these symptoms are demarcated from mood disorders, and assess the possibility that symptoms of emotional impulsivity and deficient emotional self‐regulation should be considered as core symptoms. We addressed psychiatric comorbidities, the effects of ADHD treatments on associated emotional dysregulation, and the utility of current rating scales to assess emotional symptoms associated with ADHD. Results Emotional symptoms are common and persistent in youth and adults with ADHD. Although emotional symptoms are common in other psychiatric disorders, emotional impulsivity (EI), and deficient emotional self‐regulation (DESR) may be sufficiently specific for ADHD to function as diagnostic criteria. Conclusions Emotional symptoms in ADHD cause clinically significant impairments. Although there is a solid theoretical rationale for considering EI and DESR to be core symptoms of ADHD, there is no consensus about how to define these constructs sin a manner that would be specific to the disorder. An instrument to measure EI and DESR which demarcates them from irritability and other emotional symptoms could improve the accuracy of diagnostic criteria for ADHD. - Journal of Child Psychology and Psychiatry, EarlyView.