Objectives: To examine the relationship between technical reaction time and core stabilization in taekwondo athletes. Methods: Cross-sectional correlational study of healthy male and female taekwondo athletes (n = 41; mean age 12.76 ± 1.07 years). Reaction performance was assessed using FITLIGHT Trainer sensors mounted on a taekwondo striking stand. Core stabilization was assessed using the Stabilizer Pressure Biofeedback Unit (PBU), a device employed to evaluate core muscle stabilization and deep abdominal muscle function. Spearman correlations (non-normal data) and Mann–Whitney U tests (sex comparisons) were applied. Results: Shorter reaction times were associated with a higher number of successful strikes (p<0.05). Higher PBU task performance (time held) of the transversus abdominis muscle and multifidus muscle correlated with higher strike success rates. In unadjusted comparisons, male athletes achieved more successful strikes on both right and left sides and completed tasks with fewer errors; however, after adjusting for age, height, and weight, sex was not a significant predictor of outcomes. Transversus abdominis PBU task performance (time held) was significantly higher in males in unadjusted analyses, indicating superior core stabilization compared to females. Conclusion: These findings suggest that deep core muscles are important not only for postural stability but also for dynamic motor performance.