A think tank (or policy institute) is an organization that conducts research and engages in advocacy in areas such as social policy, political strategy, economics, military, technology issues and in the creative and cultural field. Most think tanks are non-profit organizations, which some countries such as the United States and Canada provide with tax exempt status. Other think tanks are funded by governments, advocacy groups, or businesses, or derive revenue from consulting or research work related to their projects.

The following article lists global think tanks according to continental categories, and then sub-categories by country within those areas. These listings are not comprehensive, given more than 4,500 think tanks exist world wide. In general, this article is an introduction to the think tank landscape, and provides a way to quickly navigate to those of interest.

While the term "think tank" originated in the 1950s, such organizations date to the 19th century. The Institute for Defence and Security Studies (RUSI) was founded in 1831 in London. The Fabian Society in Britain dates from 1884. The Brookings Institution began in Washington in 1916.