The question of how to give meaning to the concept of sustainability in architectural design practices is highly contested today. Although architects, engineers, clients, politicians, and others seem to agree that sustainability must be addressed, behind this apparent consensus many ambiguities, contradictions, and open questions emerge. Opinions largely vary on how to define the sustainability challenges that architectural design is to respond to, how to align the various stakeholders involved, which scales and elements to consider, and how to transform these questions into design strategies, spatial configurations, and materiality of buildings. These practices cannot be confined merely to technological problem-solving as they essentially mesh a range of cognitive, social, cultural, and material elements. This article draws on the interdisciplinary field of Science and Technology Studies (STS) to set out the transferable analytical framework of ‘translation’ through which to explain how the concept of sustainability is continuously transformed within contingent, complex, and dynamic architectural design practices as buildings materialize. The framework of translation is particularly well adapted to unpack claims, make them more accountable, and thereby support the larger project of sustainability.