Objective To investigate the impact of Tai Chi training on muscle strength, physical endurance, postural balance and flexibility, as measured by tests commonly used in healthrelated fitness or competitive sports contexts. Design Systematic review and meta-analysis. Data sources The following databases were searched up to 31 July 2020: CINAHL, Cochrane Library, MEDLINE via PubMed and SPORTDiscus. Eligibility criteria for studies Inclusion: (1) Randomised controlled trials published in German or English; (2) Tai Chi used as an intervention to improve physical performance; (3) Test methods commonly used in health-related fitness or competitive sports and (4) Participants aged ≥16 years (irrespective of health status). Exclusion: (1) Studies not focusing on Tai Chi or including Tai Chi mixed with other interventions and (2) Modified or less than eight Tai Chi movements. Results Out of 3817 records, 31 studies were included in the review, 21 of them in the meta-analysis. Significant improvements in handgrip strength (2.34 kg, 95%CI 1.53 to 3.14), walking distance during 6min (43.37m, 95% CI 29.12 to 57.63), standing time in single-leg-stance with open eyes (6.41 s, 95% CI 4.58 to 8.24) and thoracolumbar spine flexibility (2.33 cm, 95% CI 0.11 to 4.55) were observed. Conclusion Tai Chi training seems to moderately improve physical fitness when evaluated by tests used in health-related fitness or competitive sports. Moreover, thoracolumbar spine flexibility seems to be a factor in the improvement of postural balance. Further research is needed, including younger healthy participants performing a widely used, standardised form (eg, Peking-style routine) with high-intensity movements (eg, use of lower stances).