This Irish policy network research forms part of a larger international study of climate change networks (www.compon.org) where we identify a range of organisations which share an interest in climate change related issues. These organisations are tied together in relatively stable sets of relationships. Using exponential random graph models, we test a number of different combinations of theoretically motivated action-based explanations for understanding the behaviour of network actors. We explore the underlying dynamics and stochastic processes that interact to shape the structure of the Irish climate change policy network.