A drop-prevention tool harness for pistol-grip hand tools includes a sleeve member sized to be installed around a gear housing of a pistol-grip hand tool. A tool body strap defines a flattened closed loop that extends around a wall of the sleeve member and extends to a rearward end portion spaced apart from the sleeve member. A handle strap is connected to the rearward end portion of the tool body strap and has first and second handle strap portions that extend to respective first and second handle strap end portions each defining a closed loop. The first closed loop is sized to permit passage therethrough by the second handle strap end portion. An optional handle band is sized and constructed to be installed around the handle strap and hand grip of a pistol-grip hand tool.