PURPOSE: To test the assumption that person-first language (PFL) reduces obesity stigma, mediated by perceived personal responsibility for obesity. DESIGN: Cross-sectional, experimental. SETTING: Online, United States. PARTICIPANTS: 299 young adults. MEASURES: Participants read a vignette using PFL or identity-first language (IFL) or about someone without obesity. Participants reported perceived personal responsibility for obesity, and 3 operationalizations of obesity stigma: prejudice, stereotypes, and support for punitive policies. Mediation analyses were used to test if the manipulation affected obesity stigma, through perceived personal responsibility. RESULTS: There was no indirect effect of PFL vs IFL on the 3 outcomes (95% CIs contained zero). However, the indirect effects of PFL vs no-obesity condition were significant (prejudice: CONCLUSION: PFL may not affect obesity stigma as it does in the context of other marginalized groups. The effect of PFL and IFL, compared to the no-obesity condition, suggests future routes for intervention.