OBJECTIVES:To explore sports organisation members' attitudes to sponsorship of sport by energy-dense, nutrient-poor food and drink ('junk food') brands. STUDY DESIGN:The study design is a cross-sectional study. METHODS:An online survey of adult members of three sports organisations that did not accept junk food sponsorship in Victoria, Australia in 2018: one was responsible for an elite team in a national competition (5000-10,000 members); one managed a team sport competition across Victoria (50,000-100,000 registered junior and adult participants, referees and coaches); and one administered a junior team sport competition for boys and girls in a major city (10,000-15,000 participants). RESULTS:Most (71%) of the 2224 respondents reported it was important/very important that their organisation did not accept junk food sponsorship. A higher proportion was concerned/very concerned about junk food companies sponsoring children's sport (60%) compared with such companies sponsoring elite (49%, P < 0.001) or community adult (39%, P < 0.001) sport. A higher proportion of respondents were likely/very likely to support a policy that restricted junk food sponsorship of children's sport (84%), compared with a policy restricting sponsorship of elite (76%, P > 0.001) and adult community (74%, P > 0.001) sport. Two-thirds of respondents supported restricting junk food companies from sponsoring sport, even if fees for children's (66%) and community adult (65%) sport increased, or if membership and attendance costs for elite sport supporters increased (63%). CONCLUSIONS:In the Australian context of this study, junk food sponsorship of sport, particularly children's sport, is a concern to members of sports organisations. Although still high, support for restricting such sponsorship declines if members perceive it will lead to increases in participation costs and decreases in participation opportunities. Initiatives restricting junk food sponsorship of sport are likely to receive strong support from the sports community, particularly when the focus is on children's sport, and participation costs and opportunities are not negatively impacted.