This randomized controlled trial showed basketball skill performance during all timed and shooting drills declined progressively as dehydration increased. Total time to complete basketball-specific movement drills (including sprinting, defensive slides, sprinting-defensive slides combination, and repetitive jumping drills) was slower, and fewer shots (foul-line and baseline jump shots, layups, three-point, 15-ft, free throws) were made in the dehydrated group compared to hydrated controls.