Trans* inclusion in sports is a highly debated topic, with policy views cutting across party lines. While minority rights research suggests attitudes towards a minority group are central to framing one's policy view, recent descriptive studies on trans* inclusion in sports suggest resistance might be grounded in fairness concerns, rather than trans* negativity. This research aims to clarify the causal relationship between trans* attitudes, fairness concerns, and policy views. First, through a theoretical framework grounded in sport ethics literature, I argue that fairness concerns are driven by assumptions about trans* individuals' physiology, ideas about the value of sports, and particularities of competitions. Next, this paper argues that different sport competitions produce varying levels of fair play concern which, in turn, influence the relationship between attitudes and support for inclusionary policy. Using an online survey experiment conducted in the US (N = 1218, Mage = 48.42, sd = 16.97) this study finds support for the framework and suggested causal relationship. The results indicate that on average, the public is more willing to support trans* inclusion in low (shooting) vs. high (steeplechase) fair play concern competitions. Crucially, fair play concern moderates relationships between attitudes and support for trans* inclusion, with trans* negative individuals more willing to support trans* inclusion in shooting compared to similarly prejudiced individuals in the steeplechase condition. The results have implications for minority rights literature and trans* policy advocates, suggesting it might be beneficial to address fair play concerns directly in attempts to increase support for trans* inclusion.