Employee retention is becoming a major concern in organizational management. To maintain business’ competitive advantages, companies need to keep employees working for their organizations. Thus, many firms are trying to find out how to retain their employees. This study aims to investigate determinants of employee retention of South Korean construction employees. From the review of the literature and discussions with industrial practitioners, eight significant determinants affecting employee retention in South Korean construction firms are identified. The fuzzy technique for order of preference by similarity to ideal solution (TOPSIS) is employed to prioritize the identified determinants. The fuzzy TOPSIS analysis shows that personal characteristics, personal development, promotion opportunities, and work-life balance are the four most critical determinants. Construction firms are suggested to focus on these determinants to improve employee retention rates within their companies and achieve sustainable development.