We draw on the concept of epistemic injustice to understand (1) how library workers are harmed in their capacity as knowers when their experiences of patron-perpetrated sexual harassment (PPSH) are not believed; and (2) how a lack of hermeneutical resources—the conceptual knowledge to name and identify PPSH as gender-based violence—makes it difficult for them to make sense of their experiences. Library workers are subject to epistemic injustice when their knowledge/truth claims about PPSH are dismissed, diminished, disbelieved or otherwise discounted by patrons and people in the library organization, often in favour of the perpetrator’s account. Recognizing epistemic injustice within the context of PPSH can help the library workplace move towards justice.