Abstract: An earth-retaining concrete module and an interlocked earth-retaining terraced wall system employing such modules to stabilize earthen embankments and to reduce erosion from wave action. The module comprises an upright front wall and connecting side walls which form a U-shaped structure open at the top and adapted to receive fill material therein. The side walls of the module have at least one open notch in the top of each side wall, adapted to accept in an interlocked manner the width of the bottom of the front wall of a module in the next higher row in the wall system. The module includes a plurality of holes in the side walls to permit the side walls of adjoining modules to be secured together by pins or bolts. The side walls have inward-positioned wing side walls extending from the center of the side walls toward the rear of the side walls to place the center of gravity of the module toward the rear of the module.