Background: Non-steroidal anti-inflammatory drugs (NSAIDs) are medications that are frequently used by athletes. There may also be some abuse of these substances, although it is unclear whether NSAIDs in fact enhance performance. We performed a systematic review and meta-analysis to evaluate the effect of NSAIDs on sport performance indices. Methods: We selected randomized trials from the PubMed and Cochrane Library databases investigating the effects of NSAIDs on sport performance. Volunteers could be healthy adult men and women. Any NSAID, administered by any route, taken prior to any type of exercise, and for any duration could be used. The control intervention could be a placebo, an active substance, or no intervention. We included doubleblind, single-blind, and open-label studies. The primary outcome was the maximum performance in exercises as defined in each study. The secondary outcomes were the time until self-reported exhaustion and the self-reported pain. Results: Among 1631 records, we retained thirteen parallel-group and ten crossover studies, totaling 366 and 148 subjects, respectively. They were disparate regarding treatments, dose and duration, and the type of exercise. There was neither significant difference in the maximum performance between NSAIDs and control groups nor in the time until exhaustion nor in self-perceived pain. Conclusions: The existence of an ergogenic effect of NSAIDs on sport performance indices was unable to be concluded, since the level of evidence of the studies is low, the doses tested, and the exercises performed are very heterogeneous and far from those observed in real-life practices. More studies are required.