A key challenge for gender theory and practice is to explain the circumstances in which homophobia either intensifies or declines. In addition to the important theoretical implications of such an explanation, being able to clearly delineate the mechanisms that drive the ebb and flow of homophobia raises the prospect that one day it might be possible to eradicate this important antisocial problem. But understanding the underlying drivers entails the development of a satisfactory body of theory to explain the existence of homophobiaa body of theory that may well be called on to explain different homophobias in different cultural settings that span the gender spectrum. As discussed, various proposals have been made for alternative terminologies and associated candidate theories that are intended to explain homophobia better. However, none seems to have articulated a sufficiently compelling case to be considered definitive, while others simply fail to accord with everyday homophobic experiences. The purpose of this paper is threefold. First, to propose a set of criteria that need to be satisfied if a theory is going to provide a robust explanation for the ebb and flow of homophobia(s). Second, to explore whether gender taboos offer a coherent theoretical basis for explaining the existence of, and the power behind homophobia. Finally, the analysis looks to shifting gender relations as a possible explanation for the ebb and flow of homophobia. Keywords masculinity; masculinities; inclusive masculinities; masculine taboos; gender roles; gender taboos; homophobia; homophobia-phobia; homophobiaphobia; homohysteria; gender taboo theory; homophobia theory Introduction: The ebb and flow of homophobia Homophobia is an important social problem that exacts a heavy toll on the wellbeing of men and women around the world (Berrill, 1992; Tin, 2008). The prospect of being able to better understand what drives homophobic prejudices and what causes them to fluctuate, raises the possibility that it might be possible to intervene and ultimately to be free of these harmful antisocial phenomena. In their important work, McCormack and Anderson (2014) have found evidence for declining levels of homophobia in circumstances where homophobia was previously well established, especially in all male institutions, schools, colleges and sporting teams in the US and UK. At around the same time, McCann reported evidence from Australian men that suggests that homophobia can be unlearned (McCann, Minichiello & Plummer, 2009). Moreover, there is also evidence that reductions in homophobia can be circumstantial and highly circumscribed. For example, in Anglophone cultures, homophobia typically interdicts intimate male-male contact in public spaces, but this interdiction can be readily suspended in the case of members of a winning football team, who are momentarily free to embrace, cry and kiss each other on the playing field in front of spectators to celebrate a hard fought victory (for more, see Plummer, 1999, pp. 257-266).