Learning how to manage emotions such as frustration and disappointment is an important task of childhood. Although it is common for very young children to have temper tantrums when they cannot get their way, these reactions tend to decrease in frequency and intensity for most children as they develop skills to help them respond in more adaptive ways. For some children, however, skills in regulating emotional reactions do not develop as expected. Difficulties with emotion regulation are often manifested in characteristics and behaviors such as low frustration tolerance, volatile temper, aggressive response to low provocation, and general irritability. These types of responses are part of the clinical picture of a number of mental health disorders in youth listed in the DSM-IV including ADHD, PDD, major depression, and bipolar disorder. Another disorder involving emotion dysregulation being considered for inclusion in DSM-V is disruptive mood regulation disorder. It is postulated that the capacity to regulate emotions is a function of biology (e.g., genetic substrates), environment (e.g., parental modeling), and interactions between the two. In this article, the authors review the results of several recent investigations that have examined aspects of emotion regulation in youth to provide school psychologists with an overview of this construct and the types of research that are being conducted in this area.