Beta-alanine is an amino acid precursor of carnosine and that receives attention in scientific publications as a supplement for improving sports performance. Beta-alanine supplementation provides an increase in muscle carnosine stores, which results in effective buffering, especially in high-intensity exercise. Therefore, the present study aimed to carry out a systematic review of the effect of beta-alanine supplementation on sports performance. After defining the inclusion and exclusion criteria, 24 randomized, placebo-controlled studies were included in this systematic review. Of these, 18 showed positive results from the supplementation of this amino acid on performance. In our study, we can conclude that beta-alanine supplementation can contribute to sports performance, especially in high intensity and short duration activities. Chronic beta-alanine supplementation with doses ranging mainly between 2.4 and 6.4 grams per day, for 4 to 12 weeks, has been shown to be effective in terms of performance. Despite several studies related to the effectiveness of beta-alanine use and the buffering effect of muscle carnosine, more studies are needed to assess the different responses that can occur, especially considering the differences between men and women, age groups different types of exercises, different doses, and durations.