Sei or SEI may refer to:
Arts Sei (album), a 2012 album by Nando Reis, or the title song Sei, a 2025 album by Kaki King Sei (film), a 2018 Tamil thriller film
Organizations and companies 7-Eleven, a popular multinational chain of gas stations and convenience stores Safety Equipment Institute, a private, non-profit organization established to test safety and protective products Scottish Episcopal Institute, the theological college of the Scottish Episcopal Church Script Encoding Initiative, a department at UC Berkeley supporting proposals for minor and historic scripts in the Unicode Standard. Scuba Educators International, a non-profit diver training organization SEI Investments Company, a financial services company headquartered in the United States Slough Estates International, the former name for Segro Smith Enterprise, a firearm and accessory manufacturing facility based in Tempe, Arizona that is known for making flash suppressors, muzzle brakes, sound suppressors, M14 rifles and accessories for M14 rifles. Software Engineering Institute, a federally funded research and development center at Carnegie Mellon University SpaceWorks Enterprises, a small aerospace engineering company in the United States Stockholm Environment Institute, a non-profit institute that specializes in sustainable development and environmental issues Sustainable Endowments Institute, a special project of Rockefeller Philanthropy Advisors, Inc, the Sustainable Endowments Institute (SEI) has pioneered research, education and outreach to advance resilient institutional responses to the climate crisis. Sumitomo Electric Industries, a manufacturer in automotive, information and communications, electronics, environment and energy, and industrial materials SUNY Eye Institute, a medical and basic sciences research institute in New York
People Given name Shō Sei (1497–1555), king of the Ryukyu Kingdom from 1526 to 1555 Shō Sei (r. 1803), king of the Ryukyu Kingdom in 1803 Sei Andō (born 1983), Japanese stage actress Sei Ashina (born 1983), Japanese actress Sei Fujii (1882–1954), Japanese male immigrant rights activist in the United States Sei Hatsuno (born 1976), Japanese male writer of mystery and thriller novels Sei Hiraizumi (born 1944), Japanese actor Sei Ikeno (1931–2004), Japanese composer Sei Itō (1905–1969),Japanese Modernist writer of poetry, prose and essays, and a translator Sei Kawahara (born 1995), Japanese male figure skater Sei Matobu (born 1976) Japanese actress Sei Muroya (born 1994) Japanese professional footballer Sei Shōnagon (966–1017 or 1025), Japanese author, poet, and court lady Sei Soga (1882–1970) Japanese activist and community leader in Hawaii Sei Yoshida (1909–1976) Japanese politician A member of girl group Weki Meki
Surname Indrek Sei (born 1972), Estonian freestyle swimmer Sadao Sei Japanese astronomer who discovered an asteroid in 1983
Other uses Sei whale, a baleen whale Se'i, traditional bacon from Timor, Indonesia Subjective Effect Index, a website documenting and classifying the effects of psychedelic drugs Seebeck effect imaging, uses a laser to generate thermal gradients in conductors in order to locate electrically floating conductors Secondary electron image, a type of imaging in scanning electron microscopes to view sample topography Seri language, spoken in two Mexican villages Service endpoint interface, a term used in Java Platform, Enterprise Edition when exposing Enterprise JavaBean as web service Social-Emotional Intelligence (see Emotional Intelligence) Space Exploration Initiative, a plan envisioned by former U.S. President George H.W. Bush with crewed Moon and Mars missions Spanish East Indies, a former Spanish colony comprising the Philippines and most of Micronesia Solid electrolyte interface 清 (disambiguation) 聖 (disambiguation)