Expanding Miranda Fricker's (2007) concept of epistemic injustice, recent accounts of agential epistemic injustice (Lackey, 2020; Medina, 2021; Pohlhaus, 2020) have focused on cases in which the epistemic agency of individuals or groups is unfairly blocked, constrained, or subverted. In this article I argue that agential epistemic injustice is perpetrated against marginalized groups not only when their group epistemic agency is excluded, but also when it is included but receives defective uptake that neutralizes their capacity to resist epistemic oppression. I (...) identify two harms that such injustice inflicts on marginalized groups: epistemic disempowerment and critical defanging of resistant epistemic group agency. My analysis shows how the harms of agential epistemic injustice can occur through unfair epistemic exclusions in group dynamics, but also through forms of inclusion in group dynamics that distort or coopt the epistemic agency of the group. Following Emmalon Davis (2018) and her analysis of epistemic appropriation, I argue that the harms of agential epistemic injustice can occur when the resistant epistemic resources of a marginalized group are appropriated in a way that disempowers them and critically defangs their resistant epistemic agency. I use Taylor Rogers’ (2021) analysis of the epistemic appropriation of “#MeToo” and “intersectionality” to show how epistemic disempowerment and critical defanging work in unjust epistemic group dynamics. The article offers a diagnosis of the failures of epistemic responsibility involved in agential epistemic injustice, and some suggestions for resisting those failures and working toward more responsible and just epistemic group dynamics. (shrink)