Jei or JEI may refer to:
- Jamaat-e-Islami
- Jane Castro (born 1982), American entertainer
- Islamic Republic of Iran (Jomhuri-ye Eslāmi-ye Irān)
- Journal of Electronic Imaging
- Yei language, spoken in Papua New Guinea
- Jei, a character in Usagi Yogimbo
- Jei, member of South Korean girl group Fiestar
- JEI Corporation, a South Korean educational company