A breakaway safety shut-off valve including a valve housing and a detachable end portion connected thereto by a region of reduced strength. The housing includes an axial passage and the detachable portion includes an annular shoulder positioned adjacent the region of reduced strength. A ball is guidably displaceable along a circumferential surface of the axial passage between an open position and a closed position, with a spring engaged between the valve housing and the ball to urge the ball toward the closed position. An insert having a plurality of arm segments is engaged between the ball and the annular shoulder to initially maintain the ball in the open position. At least partial detachment of the detachable portion along the region of reduced strength causes at least one of the arm segments to disengage the annular shoulder to permit the spring to displace the ball toward the closed position.