Between 1969 and 1995, at least thirty diagnosed transsexual workers brought their employers before state and federal courts and agencies. Diagnosed transsexual workers were an extremely small sub-group within the wider universe of gender-nonconforming people. Already subjected to institutional bottlenecks that disproportionately limited medical treatment to white, wealthy, abled, heterosexual, and “passable” gender-crossers, diagnosed transsexuals were further restricted by an “unwritten rule” mandating their invisibility and active disassociation from (and, indeed, disavowal of) other, more marginalized queer people. While this “unwritten rule” offered some, diagnosed transsexuals a limited and conditional ability to assimilate into the white, middle-class mainstream, it also prevented diagnosed transsexuals from forming collaborative, street-level activist organizations with which to challenge discriminatory treatment. As a result, when these workers were fired or harassed shortly after their employers had learned that they were receiving or had undergone gender-affirming medical treatment, workers sought protection instead from an emerging liberal state. Using new laws designed to protect U.S. workers from sex- and disability-based employment discrimination, these workers brought legal challenges before a host of state and federal courts and agencies. Their claims forced state officials to grapple with the heretofore undefined categories of “sex” and “disability” and to ultimately (re)construct them in trans-exclusionary ways. These cases highlight the vastly uneven and occasionally contradictory nature of the U.S. “Cis States,” which by 1992 mostly extended employment protections only to workers who remained in the sex they were assigned at birth. In the end, because their legal actions were not paired with a significant extra-legal activist effort, most transsexual workers failed to find relief from the state. Although a few of these claimants have been briefly discussed in other historical texts, this dissertation is the first to holistically examine their employment-discrimination claims. Standing at the intersections of modern U.S. history, political history, the history of sex, gender, and sexuality, activist studies, labor history, and legal studies, it not only complements research on gay and lesbian political history but also presents an alternative narrative in which discrimination against transsexual workers set the stage for discrimination against cisgender sexual and racialized minorities.