Introduction. Chronic Obstructive Pulmonary Disease (COPD) people suffer from severe physical impairments, which often elicit significant psychological distress and impact their quality of life. This meta-analysis aimed to assess evidence from the scientific literature on the effects of relaxation techniques. Methods. We investigated 9 databases to select 25 RCTs. Studies included both inpatients and outpatients with COPD. Both respiratory and psychological outcomes were considered. Results. Relaxation techniques showed a little positive effect on the value of the percentage of predicted FEV1 (d = 0.20; 95% Cl: 0.40--0.01) as well as a slight effect on levels of both the anxiety (d = 0.26; 95% Cl: 0.42-0.10) and depression (d = 0.33; 95% Cl: 0.53-0.13). The higher effect size was found in the quality of life value (d = 0.38; 95% Cl: 0.51-0.24). The assessed quality of the studies, based on the PEDro Scale, was generally medium/high. Conclusion. Relaxation training can have a moderate impact on both psychological well-being and respiratory function, resulting in noticeable improvements in both. Although higher quality research is required, our results sustain the importance of relaxation techniques as a tool to manage COPD.