A transparent spherical toy includes upper and lower shell halves. The upper shell half has a bottom end face, a thickness reduced rim portion extending downwardly from the bottom end face, an outer recess formed outside of the inner space and extending upwardly from the bottom end face, and a male thread formed on the rim portion. The lower shell half has a top end face, an inner wall, a ring-shaped shoulder projecting into the inner space from the inner wall adjacent to the top end face so that the rim portion is seated against the shoulder, a female thread formed on the inner wall between the top end face and the shoulder and engaging the male thread, and a notch formed in the top end face above the female thread and aligned with the outer recess. The transparent spherical toy further includes a sealing ring disposed between the shoulder and the rim portion for providing sealing therebetween when the male and female threads engage each other tightly, and a dog mounted rotatably in the outer recess and extending therefrom into the notch for preventing the upper shell half from rotating relative to the lower shell half.