This working paper lays out the rationale and conceptual background of thinking of public transport as public space. The purpose of the paper is to provide an overview of current debates surrounding the conceptualisation of public transport as public space from the point of view of public space and critical transport/mobility literatures, to identify research needs, and to discuss possible multidisciplinary approaches for further work. The paper is published in the Leibniz-Institut für Länderkunde's Forum IfL series.