Purpose: Clinical supervision is a dynamic and collaborative ongoing process in speech-language pathology. This study aims to prepare the supervisor certification standards of the Korean Association for Speech-Language Pathologists (KSLP) and the contents of the professional development courses. Methods: A total of 611 Korean speech-language pathologists (SLPs) (52 males, 559 females) completed the Google online survey regarding their perception and demand on the qualifications and core competencies of supervisors and supervisor training courses to develop SLP’s leadership and professional competencies. Results: 74% of respondents believed that a supervisor training courses was necessary to strengthen the professionalism and competence of SLPs, and 79% perceived they were willing to receive clinical supervisor training. Regarding supervisor qualification requirements, 53% answered that the clinical experience required for supervisor qualification was more than 10 years; the highest response rate was 10 hours (53%) of introductory courses and 10 hours (62%) of advanced courses. Respondents felt that an interval every two years was most appropriate (49%) for professional development requirements. The fundamental concepts of knowledge, skills, core competencies, and supervision that supervisors should have were also addressed and discussed. Conclusions: The current survey identified common perceptions and strong demands for a systematic supervisor training framework. The results derived from supervisees’ high demand and awareness can serve as a starting point for developing standards for the supervisee-centered supervisor system of speech-language pathology in Korea.