Gemma Frisius is a lunar impact crater that is located in the rugged southern highlands of the Moon. It was named after Dutch physician Gemma Frisius. It lies to the north of the walled plain Maurolycus, and southeast of the smaller crater Poisson. The crater Goodacre is attached to the northeast rim. The southeastern rim of the crater is also worn, and the inner wall has slumped nearly a third of the distance across the interior floor. The remainder of the floor is relatively level and deep, with a central peak that is offset to the northwest of the midpoint.