Abstract: A tool is provided for the cleaving or separation of optical fibers so as to provide a flat perpendicular end face for the fiber. In the cleaving process, fiber is inserted into a slot and extends between an opposing scribe and anvil positioned at the end of the slot. In order to cleave the fiber, the fiber is first moved in a direction towards the scribe which, when it touches the fiber, produces a mark or surface imperfection on the outer surface of the fiber or its cladding. After scribing, the fiber is moved in an opposite direction over the anvil at which point the fiber is broken at the scribe mark. In one embodiment means are provided to press the fiber over the anvil for more precise cleaving.