Banks play an important role in attempting to make the transition to a more sustainable society. They can assist with the establishment and growth of new industries that have smaller ecological footprints and move investments away from environmentally damaging sectors. Conventional banks have, however, come under increasing criticism for the negative social and environmental impacts of the economic activities that they continue to support. This has led to a backlash by some investors, resulting in a push for more ethical and sustainable financial institutions. The aim of this chapter is to consider whether Bank Australia is an example of sustainable banking and whether the cooperative customer-owned model on which it is based has broader implications for transformative change within the sector. Overall, it is argued that under the right circumstances, sustainable and ethical banking is possible.