Purpose: The current study examined the effects of taekwondo coaching language training on coaches’ self-efficacy of language use, coaching confidence, and perceived coaching behavior. Methods: A total of 72 taekwondo instructors in Korea participated in a single day coaching language training session designed to enhance their proper coaching language use. The 10-hour training program covered positive coaching language that recommended for the coaches to used in 11 taekwondo coaching situations. The training program was developed based on coaching behavior literature and other motivation theories such as goal orientation perspective. They answered to the questions on self-efficacy of coaching language use, coaching confidence, and perceived coaching behavior before and after the training session. Open-ended questions on their perceptions of the training were also administered. Results: Paired t-tests and effect sizes revealed that the training session had relatively high effect on enhancing instructors’ self-efficacy of language use (effect size 0.49 - 1.02). The training resulted in greater coaching confidence (0.69 - 0.82). In addition, they felt that they would able to show more positive coaching behaviors such as encouragement and instruction. Conclusion: The results confirmed that the single day language use training program had positive impacts on instructors proper use of coaching language and corrective behaviors.