Thin may refer to:

• a lean body shape. (See also: emaciation, underweight)
• Thin (film), a 2006 HBO documentary about eating disorders
• Paper Thin (disambiguation), referring to multiple songs
• Thin (web server), a Ruby web-server based on Mongrel
• Thin (name)

• All pages with titles beginning with Thin
• All pages with titles containing Thin
• Thin client, a computer in a client-server architecture network.
• Thin film, a material layer of about 1 μm thickness.
• Thin-film deposition, any technique for depositing a thin film of material onto a substrate or onto previously deposited layers
• Thin film memory, high-speed variation of core memory developed by Sperry Rand in a government-funded research project
• Thin-film optics, the branch of optics that deals with very thin structured layers of different materials
• Thin layer chromatography (TLC), a chromatography technique used in chemistry to separate chemical compounds
• Thin layers (oceanography), congregations of phytoplankton and zooplankton in the water column
• Thin lens, lens with a thickness that is negligible compared to the focal length of the lens in optics
• Thin Lizzy, Irish rock band formed in Dublin in 1969
• Thin Man (disambiguation)
• The Thin Blue Line (disambiguation)
• Thin capitalisation