This study aimed to determine the effects of an Anger Coping Programme based on cognitive behavioural techniques on adolescents' anger, aggression and psychological symptoms. In this randomized controlled experimental study, 385 ninth-year high school students in Turkey were administered the State-Trait Anger Expression Inventory, the Aggression Scale and the Brief Symptom Inventory in 2011-2012. Of the 385 students, 62 who met the inclusion criteria were randomly assigned to experimental and control groups by gender and the scores they obtained from the scales. The students in the experimental group met 1day a week for 1.5h, and the study lasted 10weeks. The scales were administered three times: before the programme was started, immediately after the programme was completed and 6weeks later. The Anger Coping Programme was effective at reducing students' anger and aggression levels, and a range of psychological symptoms except for somatization.