G
- Larry Gaines – The Roads Must Roll
- Galahad – Time Enough for Love
- Gay Deceiver – The Number of the Beast, To Sail Beyond the Sunset, The Cat Who Walks Through Walls
- Frederica "Ricky" Gentry – The Door into Summer
- Alec Graham / Alex Hergensheimer – Job: A Comedy of Justice
- Joe Green – Gulf
- Oscar Gordon – Glory Road (also appears briefly in 'The Number of the Beast)
Read more about this topic: List Of Robert A. Heinlein Characters