This paper explains how their culture is an important influence on the capacity of organisations to adapt to climate change. It reports on a case study of four organisations interacting in the Reefplan water quality improvement program on the Great Barrier Reef, Australia. It finds that the artefacts, symbols, values and assumptions of organisations have significant influences on adaptive decision-making. These elements of culture influence decision-making, the legitimacy and flow of knowledge, and, the boundary work of organisations. What adaptive decision-making practices get adopted and their temporal persistence is also influenced by culture. This research suggests that effective adaptation governance requires constant attention to culture because it affects the expression and persistence of adaptive decision-making practices. Managed cultural change is identified as a future research direction.