Background <p>Tai Chi Chuan is a Chinese martial art style that integrates slow and rhythmic movements with synchronized breathing, classified as a mind–body modality. Its practice has been shown to positively impact health markers in various populations, including older individuals. This study reports the protocol for a randomized controlled trial, which aims to investigate the effects of a 12-week Tai Chi Chuan program, based on the Yang 16-movement form, combined with walking on physical and mental markers of older adults.</p> Methods <p>This study is a randomized, single-blinded, two-arm, parallel-group, superiority trial. Forty older adults, aged 60 to 75 years, who are not currently engaged in any systematic strength and/or aerobic training programs, will be randomly allocated on a 1:1 ratio to either an intervention group involving a 12-week Tai Chi Chuan program combined with walking, or an active-control group involving only walking, both performed twice per week. Candidates with language and cognitive problems, a history of cardiovascular diseases (except controlled hypertension), osteoarticular limitations, recent fractures, severe injuries, or prosthetic placement in the last 6 months will be excluded from the study. Physical outcomes include muscle strength (i.e., maximum muscle strength of knee extensors—primary outcome, lower limbs functional performance, dynamic muscular endurance of knee extensors, handgrip strength, and back-leg-chest strength), functional capacity, static and dynamic balance, muscle thickness, and muscle quality of quadriceps. Mental parameters include quality of life, sleep quality, cognitive function, and depressive and anxiety symptoms. Outcomes will be measured at baseline and after 12 weeks of intervention. The analysis plan will follow an intention-to-treat approach and protocol criteria.</p> Discussion <p>The conceptual hypothesis is that the intervention group involving Tai Chi Chuan and walking will lead to greater improvements in both physical and mental parameters compared to the active-control group with only walking due to its multi-component nature.</p> Trial registration <p>This protocol was prospectively registered at ClinicalTrials.gov (NCT06380413) on April 22, 2024. <a href="https://clinicaltrials.gov/study/NCT06380413">https://clinicaltrials.gov/study/NCT06380413</a>.</p>