Background: Transgender issues have become more prominent in sports. However, knowledge of and experience with supporting transgender players across soccer team staff remain unclear. This study surveyed soccer team staff in Japan and aimed to 1) evaluate staff’s level of knowledge of transgender-related terminology, 2) ascertain staff’s ability to identify transgender players and their experience in supporting transgender players, and 3) identify factors which affect staff’s knowledge and experience.Methods: A questionnaire was disbursed to coaches, physicians, and physical trainers affiliated with soccer teams between 2018 and 2019. Questions asked about 1) participant characteristics (sex, age, certified license, team categories); 2) understanding of transgender related terms, including LGBT (lesbian, gay, bisexual, and transgender), and the IOC Consensus Meeting on Sex Reassignment and Hyperandrogenism (IOC Consensus Meeting 2015); 3) ability to identify transgender players; and 4) experience in supporting transgender players.Results: In total, 478 participants were analyzed, including 30 women, 448 men, and none of the other genders. The mean age of participants was 38 ± 10 years; 443 (93%) were 33 involved in men's soccer and105 (22%) were involved in women's soccer. While 358 (75%) and 398 (83%) participants understood the terms LGBT and transgender, only 33 (7%) were familiar with the IOC Consensus Meeting 2015. Only 70 (15%) participants could identify transgender players, and 6 (2%) had experiences supporting them. Moreover, 4 (1%) had witnessed transgender players receiving cross-sex hormone treatment.Conclusion: Although a considerable proportion of soccer support staff were familiar with transgender terms, most did not have sufficient knowledge or experience with transgender athletes.