FY or fy can stand for:
- Fengyun, China's weather satellite series
- Feynmanium (Fy), a nickname for untriseptium (Uts), chemical element 137
- Firefly (airline) (IATA code), an airline based in Kuala Lumpur, Malaysia
- Fiscal year, a 12-month period used for calculating annual financial reports
- Fuck You (disambiguation), a common derogatory expression
- Republic of Macedonia (NATO country code), a country in southeastern Europe
- West Frisian language (ISO 639-1 language code), a language spoken mostly in the province of Friesland, Netherlands