A constant velocity universal joint includes a body which encloses the constant velocity joint components and provides a smooth outer surface. A semi-rigid plastic boot has a spherical surface sized to generally match the outer surface of the body. The material of the boot is sufficiently elastic to allow the boot to fit over the body, yet sufficiently resilient to snap the open end closed after the boot is placed over the body to provide a substantial seal preventing entry of debris under the seal. A retaining ring is positioned on the boot near the truncated end, the ring establishing the location of an elastic seal that contacts the outer surface of the body.