FHS
- Falmouth High School (Maine)
- Farmington High School (Utah)
- Feline hyperesthesia syndrome
- Fellow of the Horticultural Society
- Fetal hydantoin syndrome
- Fife High School
- Filesystem Hierarchy Standard
- Firestone High School
- Floating–Harbor syndrome
- Flushing High School
- Folsom High School
- Forks High School
- Framingham High School
- Frank Hurt Secondary School
- Frankfurter Hauptschule
- Franklin High School (disambiguation)
- Fredericton High School
- Frenship High School
- Frontier High School (Bakersfield, California)
- Frontier High School (New Matamoras, Ohio)
- Handspring (gymnastics)
- Hasselt railway station
- William Fremd High School