Tei can refer to:

  • Tei (singer), a Korean popular-music singer
  • Tei, Bucharest, a neighborhood in Bucharest, Romania. It is also the Romanian name for the Tilia tree.
  • Tellurium monoiodide, a chemical compound with the formula TeI

TEI as three-letter acronym can refer to:

  • TEI, the IATA code for the Tezu Airport in India
  • TEI Entertainment, American celebrity resource and entertainment company, Annaheim, CA
  • Tax Executives Institute, an association of business executives responsible for tax affairs
  • Technological Educational Institute, a type of tertiary education institute in Greece
  • Text Encoding Initiative, a consortium that develops standards for digital texts
  • Tertiary Education Institution in New Zealand
  • Total Economic Impact, a financial metric developed by Forrester Research
  • Trans Earth Injection, the procedure that a spacecraft performs to get back into the Earth's gravitational influence