F
- Duke Farnham – Farnham's Freehold
- Grace Farnham – Farnham's Freehold
- Hugh Farnham – Farnham's Freehold
- Karen Farnham – Farnham's Freehold
- Justin Foote – Methuselah's Children
- Justin Foote 45th – Time Enough for Love
- Friday aka Marjorie Baldwin – Friday
- Clark Fries – Podkayne of Mars
- Podkayne Fries – Podkayne of Mars
Read more about this topic: List Of Robert A. Heinlein Characters