Abstract: A knot tightening tool for use in mending or making a fishing net, which fishing net has a heavy rope or the like to which a flexible line such as a cord line is secured by a knot around the rope. The knot tightening tool has a pair of handles aligned in the same plane with end portions adjacent the rope and being interconnected by cross links such that rotation of the grip ends of the handles causes the end portions to move apart. Each end portion has gripping jaws that grip the free ends of the line and in the opposing movement pulls the free ends of the line, tightening the knot.