["Medical Anthropology Quarterly, EarlyView. ", "\nAbstract\nIn 2018, vaccine hesitancy marked the nationwide measles‐rubella vaccination campaign in the Indonesian province of Aceh. The hesitancy, which was supported by the provincial government, stemmed from concerns over porcine contamination in the vaccine product. “Tidak cocok” (incompatible) became a pervasive statement used to rationalize the refusal to participate in the vaccination program, permeated personal narratives, public responses to a vaccine allergy case, and an official meeting to determine the vaccination campaign's future. In this article, I theorize incompatibility as a lexical item of decoloniality. Incompatibility fosters a sense of liberation, paving a pathway to refuse tools and systems considered unfit according to locally situated knowledge and historical experience. It further reclaims what has been marginalized, delegitimized, and ignored by dominant epistemic and political structures. I also suggest that many Islamic expressions arising during the vaccine hesitancy have given a distinct local flavor to the decolonial critique on vaccination. [Aceh, decoloniality, incompatibility, Indonesia, Islam, vaccine hesitancy]\n"]