Abstract: A reversible safety wire pliers is disclosed which includes a sleeve mounted on one arm of the pliers, the sleeve having a double spiral shank with left-hand and right-hand grooves enclosed therein. A pair of externally toothed gears are mounted on the shank, each gear having a pair of diametrically opposed internal guide tooth seated in the left-hand or right-hand grooves such that the gears will rotate in opposite directions as the shank is pulled through the sleeve. A pair of gear-engaging plates are pivotally carried in a slot in the sleeve and when pivoted in one direction will engage the associated gear, thereby locking it in relation to the sleeve, and will disengage from the associated gear when pivoted in the opposite direction. A slide switch and spring are utilized to selectively engage one gear while simultaneously disengaging the other. A hook in combination with a biased, slidable, slotted, receiving member is used to automatically lock the plier arms in the closed position.