Isan is a region of Thailand.

Isan or ISAN may also refer to:

• Isan (band), a British electronic music group
• Isan (town), a town in Thailand
• Isan people, an ethno-regional group of people native to Northeastern Thailand
• Isan language, the collective name for the dialects of the Lao language as they are spoken in Thailand
• Isan, a dialect of the Yopno language of Papua New Guinea
• Institute for Spectroscopy Russian Academy of Sciences
• InStore Audio Network, a supplier of background music for supermarkets and drugstores
• International Society for Autonomic Neuroscience
• International Standard Audiovisual Number, a unique identifier for audiovisual works

• Saint Isan, 6th-century saint of South Wales
• Isan Díaz (born 1996), Puerto Rican baseball player
• Isan Reiyu, the Japanese name of Zen Master Guishan Lingyou (771-853)
• Isan Reynaldo Ortiz Suárez (born 1985), Cuban chess grandmaster

• All pages with titles beginning with Isan
• Isani (Tbilisi Metro), a metro station in Tbilisi, Georgia
• Isa (disambiguation), of which Isan may be an adjective form
• Esan (disambiguation) of Nigeria, which can refer to the region, people, and language