This chapter presents a holistic investigation into construction culture from an organisation studies as well as project management perspective, mobilising the concept of toxic project cultures as a novel conceptual lens to explore new ways to transform the construction industry into a more dynamic, innovative, and socially responsible sector. All levels of culture will need to change, and to be effective, attention on the part of project leadership to the change process is required on an everyday basis. Inter-organisational strategic change projects can serve as 'temporary trading zones', in which actors from different organisations bring in different work practices, narratives, norms, and values, thus creating opportunities for experimenting, knowledge exchange, and changing behaviour. In these arenas, doing things in unusual ways should always be on the agenda, to unlearn ingrained routines. Unlearning involves very different cognitive processes to learning.