Background: Improving the quality of emergency nursing care requires enhancing triage competency through education programs that integrate the content of the Korean Triage and Acuity Scale, a triage system specifically developed for the Korean context. Thus, this study developed a competency-based triage education application (CTEA), based on the Korean Triage and Acuity Scale, and evaluated its effectiveness through usability testing. Method: The CTEA used various teaching methods and game mechanisms, including lectures, case studies, and video-based scenarios, to improve triage competency. Results: In the usability testing phase, the CTEA was refined through expert heuristic evaluation and user interviews con-ducted with the think-aloud method. Six themes were derived from the interviews, highlighting the need for a well-structured program with realistic scenarios, easy accessibility, gamification, functional improvements, and future triage educational applications. Conclusion:These findings suggest that the CTEA is effective and satisfactory for users and can contribute to improving the triage competency of emergency nurses. [J Contin Educ Nurs. 2024;55(1):33-41.]