Australia is a region with one of the highest solar energy adoption rates per capita in the world. This study investigated the spatial distribution and related socioeconomic factors behind residential solar energy adoption. Residential solar panel installation data were collected for the 2563 postal areas of Australia. Through spatial autocorrelation analysis, this study revealed spatial aggregation and identified hot and cold spots in terms of the installation rate (the proportion of households with solar panels). Areas with high installation rates were clustered in South Australia, Queensland and Western Australia, while areas with low installation rates were clustered in the Northern Territory, New South Wales, the Australian Capital Territory, Victoria and Tasmania. Furthermore, this study selected eight out of 25 socioeconomic factors and found their influential mechanisms on the solar panel installation rate. Areas with high installation rates had some similar characteristics, such as a mid-level of population density and personal income, with a low housing density and a young age profile, while areas with low installation rates were diverse in their socioeconomic profile. Energy policy should address the regional differences and the related socioeconomic factors identified in this study to formulate more effective incentives to promote solar technologies.