Abstract: A clay centering device for a potter's wheel consists of a flat slab mounted on an arm which has at one end a handle and at the other end is releasably engaged rotatably and in universally pivotal manner to a mounting clamp secured to the rim of the tray of the potter's wheel. By means of the handle, the slab may be moved across the potter's wheel, its normally lower edge against the top of the wheel, to contact and center a piece of clay on the revolving wheel. The slab is adjustably fixed on the arm, which is telescopically adjustable.