The GLORIA side-scan sonar system is an invaluable tool for studying the texture of the sea floor. A substantial set of computer algorithms now exist for radiometric and geometric correction of the raw GLORIA imagery. One type of artifact not presently removed is bright lines parallel to the ship track due to multiple reflections between the seabed and the sea surface. These are common where the sea floor is flat and can lead to misinterpretation. A method is presented here to suppress multiple reflections in GLORIA and other side-scan sonar imagery. As a by-product of the suppression method a value for the seabed backscattering coefficient can be calculated, giving some extra insight regarding sea-floor type for sedimentary areas. ¿ American Geophysical Union 1994