In aiming to capture the exchange processes that produce the urban environment, the concept of urban metabolism has inspired new ways of thinking about how cities can be made sustainable and has also raised criticisms about the specific social and economic arrangements in which some forms of flow are prioritised or marginalised within the city. This paper presents a comparative analysis of different approaches to urban metabolism within industrial ecology, urban ecology, ecological economics, political economy and political ecology. The analysis reveals six main themes emerging at their interdisciplinary boundaries in relation to urban metabolism, and how this concept enables new understandings of: 1) the city as an ecosystem; 2) material and energy flows within the city; 3) economic-material relations within the city; 4) the reproduction of urban inequality; 5) the governance of urban energy flows; and 6) attempts at re-signifying the city through new visions of socio-ecological relationships. The paper suggests potential areas for cross disciplinary synergies around the concept of urban metabolism and opens up avenues for industrial ecology to engage with the politics and the governance of urban development by examining the city and its metabolism.