The Royal Microscopical Society (RMS) is a learned society for the promotion of microscopy. It was founded in 1839 as the Microscopical Society of London making it the oldest organisation of its kind in the world. In 1866, the society gained its royal charter and took its current name. Founded as a society of amateurs, its membership consists of individuals of all skill levels in numerous related fields from throughout the world. Every year since 1841, the society has published its own scientific journal, the Journal of Microscopy, which contains peer-reviewed papers and book reviews. The society is a registered charity that is dedicated to advancing science, developing careers and supporting wider understanding of science and microscopy through its Outreach activities.

Joseph Jackson Lister FRS FRMS was a British opticist and physicist best known for being the father of the 1st Baron Lister.