ABSTRACT Gender-neutral pronouns, such as they/them, have been studied as a site of identity affirmation and, at other times, contestation for non-binary individuals. In this study, we draw from interviews with 123 non-binary individuals to better understand the role of pronouns in these individuals’ lives. We find that pronoun practices are ontoformative—they actively (re)construct the meanings attached to gender and gender identities. Yet, not all non-binary individuals use similar pronoun practices, resulting in diverse ontologies of non-binary identity. Half of our respondents consistently used non-binary pronouns, such as they/them, and felt they were a stable and direct reflection of identity—an approach we refer to as a fixed expression. These individuals define non-binary gender as independent from the woman/man binary. The other half of our sample held flexible pronoun expressions—they used multiple pronouns and anticipated future changes. Some of these individuals rejected the idea that pronouns expressed their identity, offering a definition of non-binary that eschewed categorical distinctions. Others embrace pronouns as identity expressing and forming, but felt that multiplicity best reflected their identity, offering a definition of non-binary as category-spanning. Our findings highlight the central and diverse role of pronouns in the social construction of non-binary ontology.