This randomized controlled trial aims to evaluate the effects of a four-week tablet-based cognitive training program on executive functions and on-court decision-making performance in adolescent female volleyball players. Fifty licensed female volleyball players aged 12 to 14 years were randomly assigned to either an intervention group or a control group. The intervention group received cognitive training three times per week in addition to routine volleyball training, while the control group continued routine training only. Executive functions were assessed using the Stroop Test, Trail Making Test-A, Go/No-Go Test, and 2-Back Test. Volleyball-specific decision-making performance was evaluated using a video-based temporal occlusion test. The study investigates whether improvements in executive functions following cognitive training transfer to sport-specific decision-making performance.