Background: Muscular strength of the upper extremities is very important in the performance of athletes, which can be improved by using Kinesio tape. Kinesio tape is an elastic therapeutic tape used to enhance muscular strength and was first used in Japan in 1970. The use of Kinesio tape has increased significantly since the 2008 Olympics, and since then, questions have been raised about its various effects. The present systematic review evaluates the evidence for the effectiveness of Kinesio tape in improving muscular strength of the athletes’,upper extremities. Methods: PEDro, Cochrane Library, Medline, Google Scholar, ScienceDirect, Scopus, UpToDate, and PubMed databases were searched from 2016 to 2020 for studies published only in English language. The combination of the terms “, Kinesiotape”, , “, Tape”, , “, Athletic”, , “, Tape”, , “, Muscle”, , “, Tape”, , “, Elastic”, , “, Tape”, , “, Strength”, , “, Tape”, , and “, Kinesiology”,was used in the search. Findings: Among 47 obtained studies, 21 most-related studies were selected. Based on the results reported, these studies were divided into two groups: 1) the studies with the results suggesting that Kinesio tape increases the muscle strength of athletes, and 2) studies with the results suggesting that Kinesio tape is effective on other factors such as range of motion and fatigue and has no effect on muscle strength of athletes’,upper limbs. Conclusion: Kinesio tape causes positive changes in athletes' performance and abilities. In addition, it can alter the timing of muscle activity and reduce the time to achieve maximum muscle activity. Moreover, the effect of Kinesio tape on different muscle activities depends on how the Kinesio tape is used and if used in the right conditions, it can be more effective.