Fein may refer to:
- Fein and Sebé, characters in the anime Zatch Bell!
- Fein (company), founded by Wilhelm Fein
- Sinn Féin, a series of political movements since 1905 in Ireland
- Federal Employer Identification Number, used by the United States Internal Revenue Service
- Fein, a caffeine powder drink additive used for energy
Read more about Fein: People With The Surname Fein