AbstractSibilant consonants are well-established as resources for the negotiation of gender and sexuality, but the origin of these links is less clearly agreed upon. Some researchers have pointed to sex differentiation in the vocal anatomy as a potential cause for gender differences in /s/, though a review of the literature indicates that learned articulatory patterns play a critical role. This article focuses on the spectral qualities of /s/ among 15 English-speaking transgender men and transmasculine individuals. Because their early socialization and physiological development is not normatively aligned with their self-defined gender identities, trans people are well-positioned to illuminate the relative contribution of physiology and identity to the gendered voice. Two analyses are presented, one of which focuses on inter-speaker variation among all 15 participants, and the other of which compares one bilingual speaker’s productions of /s/ in English and Spanish. Together, these analyses demonstrate that sex category does not determine the gender-linked acoustic characteristics of /s/. Instead, a more complex, multidimensional framework for gender that distinguishes between gender assignment, role, identity, and presentation is necessary to account for the full range of gendered phonetic styles that speakers can employ and hence to understand the process through which gendered voices arise