We study the effects of disclosing gender pronouns on interpersonal altruism. Using a nationally-representative sample of 1,000 participants, we conduct an online experiment with asynchronous dictator games in which we vary the “disclosure regime,” or whether pronoun disclosure (by receivers, to dictators) is voluntary or mandatory. We also take advantage of natural variation in receivers’ pronouns and disclosure choices. We find that the disclosure regime has little effect on aggregate dictator giving, but find suggestive evidence that Democratic dictators give slightly less when disclosure is voluntary. This result is mostly driven by Democrats giving less to those who voluntarily choose not to disclose their pronouns. We also find that both Republicans are less generous towards individuals with non-binary pronouns, independent of the disclosure regime. A further exploration of the data suggests that these results are driven by reactions to the disclosed pronouns themselves, rather than inferences about partisan identity or similarity.