AbstractAn increasingly salient policy innovation pursued by LGBT+ rights groups and socially liberal policy entrepreneurs is the right of trans people to bring their legally recorded sex in line with their lived gender by way of self‐identification. In response to these moves toward trans inclusion, a unique coalition of trans‐exclusionary (gender critical) feminists and traditionalist conservatives has emerged to challenge these reforms. This coalition of policy opponents, mirroring historical issue frames that present homosexuals as predatory sexual deviants, campaign on a salient issue frame that presents transgender individuals and the expansion of trans rights as an inimical threat to the security, safety, and welfare of (cisgender) women, particularly in single‐sex spaces. In this paper, we address two questions. First, we ask: do trans‐exclusionary “protect women” issue frames over the alleged threat of trans persons to (cis) women shape mass public opinion? Second, we ask: in a relatively LGBT+ friendly policy environment, who supports the right to self‐identification for trans individuals? We answer these questions via an original pre‐registered survey experiment embedded within the 2021 Scottish Election Study. We find that trans‐exclusionary issue frames appealing to (cis) women's safety significantly depress support for trans rights, particularly among women respondents. Highlighting these concerns is an effective means of increasing already robust opposition to reforms designed to improve the welfare of transgender individuals, which should be of concern for proponents of self‐identification policies.