Unprecedented runaway climate change and ecological degradation is argued to be caused by the dominant capitalist mode of production’s reliance on endless economic growth and capital accumulation. Businesses and organisations are expected to act in an ecologically and socially ethical way to help avert the crisis. Yet, there has arguably been little progress in this direction. The conventional ethical frameworks are generally subsumed under capitalism’s reliance on growth that effectively delegate business ethics to a peripheral and, often, contradictory pursuit, insufficient to influence ecologically and socially sustainable business conduct. We therefore explore an alternative approach by operationalising business ethics through organisational values from a post-growth perspective. By analysing the case of a social cooperative, we highlight how post-growth organisational values emerge through the organisation’s history, the members’ experience, and active contrasting to the dominant capitalist value systems. We contribute to business ethics scholarship by highlighting the potential of post-growth organisational ethics and values in creating contrasts to the dominant capitalist values. Our research further contributes to sustainability scholarship, particularly post-growth perspectives, by highlighting that organising through post-growth values in contrast to the dominant economic system is not only possible, but essential to achieve sustainability. Ultimately, our research illustrates the need for political engagement in upholding organisational ethics, in the face of the ecological crisis.