The south-west of Australia had reliable rains through the early 20^th century, and it is now an important region for agriculture on the edge of a very dry continent. Rainfall in the south-west of Australia has seen significant declines in the late 1960s, and again in the late 1990s. This was one of the most robust precipitation trends from the climate models in the IPCC 5^th assessment report. While there have been a number of studies that have aimed to attribute the contribution of anthropogenic atmospheric greenhouse gas forcing on the rainfall decline, few studies have analysed the Coupled Model Intercomparison Project Phase 5 coupled climate model results. Here we outline that there is a clear signal from anthropogenic forcing in those climate models on the decline in cool-season rainfall in south-west Australia. There is also high variability across the models, but by the end of the Historical simulations in 2005, the sign of change is the same across all models for the cool season. There has been variability in the modelled rainfall through the last century, however, no other period compares with the emphatic signal of low rainfall in the last few decades. By season, we see that the signal in spring and winter is consistent across the models, while there is large variability in autumn and summer. The relative contributions of anthropogenic forcing and natural processes to the ongoing rainfall decline over the south-west Australia will be presented.