Background/Objective: Basketball players commonly use mouthguards for protecting their mouths fromcollisions with other players. Besides, literature reports that specific types of mouthguards may becomean ergogenic device that facilitates a powerful jaw clenching, and a subsequent concurrent activationpotentiation through this remote voluntary contraction of the mandible muscles.Methods: A randomized within-subjects design was used to study the effects of this mechanism onmuscular performance (vertical jump, agi lity, bench press power and leg press power) into two differentconditions (mouthguard and no mouthguard) in high-standard basketball players (n ¼ 13). A meandifferences analysis and a responder analysis were conducted.Results: Significant improvements were found (p < 0.05) in all vertical jump protocols using themouthguard when compared to the no mouthguard conditions. However, no significant differences werefound between the two conditions in agility and power (except in one load of bench press). Nevertheless,p-values were closer to statistical significance when analyzing the total time for the agility T-Test thanwhen the first split time was under consideration (p ¼ 0.111 and p ¼ 0.944, respectively).Conclusion: This study demonstrated that the use of custom-made, bite-aligning mouthguard had anergogenic effect on jump outcomes and inconclusive results in agility T-Test in professional basketballplayers. From the results obtained in the present study, the use of this type of mouthguards seems to bemore justified in power actions on the court than in the strength and conditioning sessions at the gym inwell-trained players.