The present study investigated the extent to which arguments employed in Persian-language feminist discourse in cyberspace rely on valid argumentation schemes and the extent to which they are are susceptible to fallacies. The study analyzed patterns of argumentation and the formation of logical errors in users’ discourse. A qualitative research design employing deductive content analysis was adopted. The research corpus comprised posts and tweets related to feminist discourse published on X and Instagram. Purposive hybrid sampling was used, and argumentative units containing an identifiable argument structure were analyzed based on Walton’s (2006, 2008) argumentation schemes using a coding framework and corresponding critical questions. The findings indicated that causal/explanatory and conceptual/definitional schemes were the most frequently employed, whereas deductive and rhetorical arguments exhibited the lowest levels of logical coherence. Moreover, a substantial proportion of the arguments were not evaluated as valid from the perspective of informal logic, with emotional and identity-based patterns frequently replacing rational argumentation. The findings further suggest that fallacies are attributable not only to logical errors but also to communicative and identity-related functions. Nevertheless, the persistence of weak argumentative practices highlights the need to strengthen critical thinking education and argumentation skills in social media environments