Bigfoot is a big ape-like forest creature. She first appeared in A Foot Too Big and is voiced by Diedrich Bader.
When playing "Turtle Hunt" Mikey and Donnie were attacked by Bigfoot, who was scared and hurt, Donnie takes her to the farm house and takes care of her. Bigfoot falls for Donnie who is not interested, later Leonardo hurts her feelings and she runs to the woods. Mikey and Donnie fight The Finger to protect Bigfoot, but as The Finger discovers Bigfoot is a female he gave up on his hunt as he can't hurt a lady. At the end Bigfoot and The Finger fall in love and disappear in the woods.
In Dinosaur Seen in Sewers! appears written "Bigfoot and I are expecting" in a New York news tabloid, Implying that The Finger and Bigfoot will have a baby.
- Bigfoot is the second cryptid to be voiced by Diedrich Bader, the first being Fiskerton Phantom, a Gorilla-Cat in The Secret Saturdays.
- Unlike most depictions of Bigfoot, this incarnation is female.