Solutions to environmental problems such as climate change, biodiversity loss, and land and water resource degradation require long term integration of economic, social and environmental policies. This poses challenges to specialised, hierarchical public administration systems. The study reported here examined strategies, structures and processes to enable environmental policy integration in six Australian states and territories, and some federal arrangements. The study found that the most prominent success factors, barriers and gaps that affect environmental policy integration relate to leadership, long term embedding of environmental policy integration and implementation capacity. Factors deserving further research and policy attention include leadership, cultural change and capacity building; embedding sustainability in structures and processes; development of a long term evidence based approach; strengthening decentralised implementation arrangements; and evaluation of policy integration initiatives.