This issue of Child and Adolescent Psychiatric Clinics, guest edited by Drs. Gabrielle A. Carlson and Manpreet Kaur Singh, is Part I of a two-part issue covering Emotion Dysregulation in Children. This issue is one of four selected each year by our series Consulting Editor, Dr. Todd Peters. Topics discussed in this issue include but are not limited to: Aggression, irritability, and mood dysregulation; Measurement of Dysregulation in Children and Adolescents; The phenomenology of outbursts; Understanding, Assessing and Intervening with Emotion Dysregulation in Autism Spectrum Disorder; Dysregulation and Suicide in Children and Adolescents; Aggression and Dysregulation: A Trauma Informed Approach; Anger outbursts and aggressive symptoms in Tourette Disorder; ADHD and the Dysregulation of Emotion Generation and Emotional Expression; Dysregulation in major mental illness; and Dysregulation, Catastrophic Reactions and Anxiety Disorders, among others.