Tei may refer to:
- Sandister Tei, Ghanaian journalist and Wikimedian
- Tei (singer) (born 1983), Korean pop singer
- Tei, Bucharest, a neighborhood in Bucharest, Romania
- Tellurium monoiodide, a chemical compound with the formula TeI
- Towa Tei, an artist, record producer and DJ (b. 1965)
TEI may refer to:
- Tarlac Electric
- Text Encoding Initiative, a consortium that develops standards for digital texts
- Technological Educational Institute, a type of tertiary education institute in Greece
- Terminal Endpoint Identifier (TEI), together with Service Access Point Identifier (SAPI) the unique identification of terminal equipment in the ISDN DSS1 standard
- Tertiary Education Institution in New Zealand
- Tezu Airport in India (IATA code)
- Total Economic Impact, a financial metric (see Application Portfolio Management)
- Trans Earth Injection, the procedure that a spacecraft performs to get back into the Earth's gravitational influence
- Triethylindium, a chemical compound
- Tusaş Engine Industries, a Turkish aircraft engine manufacturer