Abstract: A stabilizer for a telescoping cylinder and rod is disclosed. The stabilizer includes a support body which carries a cylinder rod encircling clamp and a bell crank. The support body and bell crank are moved along a support track by operation of the cylinder. As the cylinder structure reaches its full extension, the stabilizer is deployed to clamp and stabilize the cylinder rod and cylinder assembly at a joint generally equidistant the ends of the cylinder and rod assembly. The stabilizer is actuated automatically by the extension of the cylinder and is returned to its initial position as the cylinder is retracted. The telescoping cylinder stabilizer provides support for the elongated cylinder and protects the cylinder and rod from damage due to flexure and bending which might occur were it not for the stabilizer.