Abstract: A hand-held optical fiber cleaving tool has a shaft for receiving a fiber which has had the end portion of the protective cover removed. A reduced diameter section in the shaft acts as an abutment, and the exposed end of the fiber is held in a V-block clamp. The clamp is spring-biased to place the fiber in tension during a circumferential scoring by a pointed scoring tool which is journaled about the shaft. The applied tension causes the fiber to break upon completion of the scoring. In an alternate embodiment which is not hand-held, support is provided for the fiber opposite the scoring tool.