Background: : Emotional disorders, such as anxiety and depression, are one of the main causes of disability worldwide. Recent reviews suggest that Acceptance and Commitment Therapy is effective in treating emotional disorders. However, they appraise mainly individual approaches. This review aimed to analyze published studies regarding the usefulness of Acceptance and Commitment Therapy, applied on a group basis, in the treatment of anxiety and depression. Methods: A systematic review of the literature was conducted using the Web of Science, from 2008 to 2019. Fifteen articles fulfilled the inclusion criteria. Results: Those patients who received interventions based on Acceptance and Commitment Therapy showed a better emotional state and greater psychological flexibility than patients in control groups without treatment. No differences are found with Cognitive Therapy and Cognitive-Behavioral Therapy. Limitations: : the studies reviewed show limitations, principally regarding sample characteristics, study design and manner in which mechanisms responsible for changes are evaluated. Conclusion: Group-based Acceptance and Commitment Therapy proved to be useful in the psychological treatment of emotional disorders. However, the heterogeneity and limitations of the studies, make it impossible to determine the exact therapeutic elements, and if they are specific to the approach and procedure of this therapy. More research would be necessary to ascertain what patient and/or intervention characteristics might improve results and what the active and specific ingredients of the therapy are. This has clinical relevance because group-based interventions could be more cost-efficient, and it would help facilitate health-care decisions aimed at giving the public access to useful treatments.