Our contemporary world is organized in a modern/colonial structure. As people, professions and practices engage in cross-country Design for Sustainability (DfS), projects have the potential of sustaining or changing modern/colonial power structures. In such project relations, good intentions in working for sustainability do not directly result in liberation from modern/colonial power structures. In this paper we introduce three approaches in DfS that deal with power relations. Using a Freirean (1970) decolonial perspective, we analyse these approaches to see how they can inform DfS towards being decolonial and anti-oppressive. We conclude that steering DfS to become decolonial or colonizing is a relational issue based on the interplay between the designers’ position in the modern/colonial structure, the design approach chosen, the place and the people involved in DfS. Hence, a continuous critical reflexive practice is needed in order to prevent DfS from becoming yet another colonial tool.