This paper seeks to identify major shifts in the Australian environmental policy agenda over the past fifty years, and discusses the possible causes of and variables affecting agenda change. The issue of what comprises ‘environment’ policy is discussed, with reference to overlaps and intersections with other policy sectors such as agriculture, public health, energy and regional affairs. While the diversity of the environment policy domain complicates any analysis of trends, there have been two persistent trends of (i) an expansion from a more narrowly to a more broadly defined suite of issue (from environment to sustainable development) and incorporation of environment into natural resource management, and (ii) an increasing diversity of policy instruments being used. Consistent with the wide variety of issues confronted, pragmatism and convenience are often as influential as political ideology or underlying trajectories. The drivers of policy change are diverse, including biophysical factors such as drought, political leaders and international policy developments, and punctuations are often better interpreted as intensification or redirections of past policy trajectories.