Shigella (/ʃɪˈɡɛlə/) is a genus of Gram-negative, facultative anaerobic, non-spore-forming, non-motile, rod-shaped bacteria closely related to Salmonella. The genus is named after Kiyoshi Shiga, who first discovered it in 1897.

The causative agent of human shigellosis, Shigella causes disease in primates, but not in other mammals. It is only naturally found in humans and gorillas. During infection, it typically causes dysentery. Shigella is one of the leading bacterial causes of diarrhea worldwide. As of 2006, the WHO reported that Shigella causes about 165 million cases of severe dysentery, with a million resulting in death each year, mostly among children in the developing world.