Mobility data, describing the locations and movements of individuals within a geographic area, are a key resource for analysing and managing transportation systems. These data are frequently summarised in the form of origin–destination (OD) matrices, where each entry represents the number of trips between a specific origin and a specific destination. While OD-matrices are a valuable tool for modelling travel demand and managing transport networks, they also raise important privacy concerns, as they may allow the identification of individuals or sensitive travel patterns when published at high spatial resolution. In this work, a k-anonymisation algorithm specifically designed for OD-matrices is presented: the ODkAnon algorithm.