A tube jacket slitting tool including first and second opposite tool portions, each tool portion including a common hinged portion at a first end for engaging the opposite tool portion. The first and second opposite tool portions are foldable about the hinged portion between an open position and a closed position. The tool includes at least one concave surface extending across the width of forming an opening, when the first and second opposite tool portions are in the closed position, through which a tube may be slid. The tool includes a blade extending inward into the opening for slitting a depth of the tube jacket as it is moved with respect to the tool. The tool includes a hinge pivot axis in the hinged portion extending in a direction substantially in the direction of the width and at an acute angle to either the plane or to the longitudinal axis of the tube or cable in the opening formed by the at least one concave surface. When the first and second opposite tool portions are folded to the closed position with the tube or cable in the opening, movement of the tube or cable with respect to the tool causes the first and second opposite tool portions to be urged toward each other.