Abstract: A shaft seal comprises a resilient sealing ring 1 with a peripheral sealing lip which is deflected axially in use so as to bear radially against a shaft. The sealing contact area 2 on the sealing lip is between predetermined limits, each defined by a change in angle of the surface of the sealing lip so that a substantial contact stress is maintained across the whole sealing contact area 2 in use. The seal can be used in an assembly including a carrier 5, 5' in which the seal is mounted. The seal can be used cooperatively with another shaft seal to prevent contaminants passing along the shaft.