Objectives: This is a protocol for a Cochrane Review (intervention). The objectives are as follows: 1. To estimate the treatment eHect of exercise interventions for children and adolescents with anxiety disorders compared to control (e.g. no treatment, waitlist, attention placebo, naturalistic usual care), on remission, symptoms, safety and acceptability outcomes. 2. To estimate the treatment eHect of exercise interventions for children and adolescents with anxiety disorders compared to other existing anxiety treatments (e.g. medication, psychological therapy), on remission, symptoms, safety and acceptability outcomes. 3. To estimate the treatment eHect of adding exercise interventions to existing anxiety treatments for children and adolescents with anxiety disorders compared to those existing treatments alone, on remission, symptoms, safety and acceptability outcomes.