Grounder is a fictional robot in the Sonic the Hedgehog universe. He is a loyal, yet dim-witted robot who serves Dr. Ivo Robotnik throughout the cartoon Adventures of Sonic the Hedgehog, along with the chicken-like Scratch. He is a short, green machine with tracks. He has a drill for a nose as well as for hands, but these hands can often be changed into things such as grappling claws or helicopter blades.

Despite his best effort's to keep up with Robotnik's demands of capturing Sonic and Tails along with his companions Scratch and Coconuts, most of them end in complete failure. His constant failure makes Robotnik shout abuse and threaten him for most of the time. Grounder is also easily tricked, as is Scratch. Sonic would usually appear in disguise, using his speed to appear as anyone from an old lady to a pizza delivery guy. Fooled time and time again by the hedgehog, Scratch and Grounder never really stand a chance.

Grounder is mainly used for comic relief, along with Scratch.

Grounder is also a Badnik in Sonic the Hedgehog and Sonic the Hedgehog 2 games, in the Labyrinth Zone and the Aquatic Ruin Zone. However, his colour is red and blue or red and gold, rather than green. They mainly attack by burrowing out of the ground or through walls.