A lockwireless, anti-rotation fitting for attachment to connectors, including a sleeve, nut, spring, and retaining washer. The sleeve is slidably inserted within the nut and the spring is inserted on the sleeve, grips it, and locks the sleeve with the nut. The nut includes a plurality of serrations which engage a tab extending from the spring. The spring, which is semi-anchored to the nut, can only rotate inwardly or in the clockwise direction. The tab of the spring may only ratchet over the serrations when a predetermined counter-clockwise or loosening torque is applied to the nut. The serrations allow for rotation in the clockwise direction, while preventing counterclockwise rotation until a predetermined torque is reached.