Guts Man G (ガッツマンG Gattsuman Gurēto, "Guts Man Great") is an upgraded Guts Man that Dr. Wily stole from a Robot Museum and modified to be the boss of the first Wily Castle stage in Mega Man 7. He now has an improved and oversized version of his Super Arm, now shaped like a clamp, which he constantly uses to make rocks fall from the ceiling, or grab hold of Mega Man and slam him into it, along with a redesigned lower body, with tank tread boots and a rocket booster that allows him to push himself into the air and bring boulders down. He can only be damaged by attacking his head. Slash Claw is his weakness, and can also throw the boulders Guts Man G brings down back at him for extra damage (though it must be used before he starts spinning his arm to throw the rock, or either he will be invulnerable to it or the rock will break upon being cut).
- A toy of Guts Man G appears on Clown Man's stage in Mega Man 8.
- Guts Man G appeared in the Rockman 7 manga.
- One of the fake Guts Mans in the Rockman 8 manga resembles Guts Man G.