The Lunar Society of Birmingham was a British dinner club and informal learned society of prominent figures in the Midlands Enlightenment, including industrialists, natural philosophers and intellectuals, who met regularly between 1765 and 1813 in Birmingham. At first called the Lunar Circle, "Lunar Society" became the formal name by 1775. The name arose because the society would meet during the full moon, as the extra light made the journey home easier and safer in the absence of street lighting. The members cheerfully referred to themselves as "lunaticks", a contemporary spelling of lunatics. Venues included Erasmus Darwin's home in Lichfield, Matthew Boulton's home, Soho House, Bowbridge House in Derbyshire, and Great Barr Hall.

The Midlands Enlightenment, also known as the West Midlands Enlightenment or the Birmingham Enlightenment, was a scientific, economic, political, cultural and legal manifestation of the Age of Enlightenment that developed in Birmingham and the wider English Midlands during the second half of the eighteenth century.