Disclosed are a method for processing video signals and an apparatus therefor. Specifically, the method for processing video signals on the basis of inter prediction comprises the steps of: inducing a motion vector predictor using motion data of a neighboring block of the current block; parsing layer data indicating the current layer to which a motion vector difference used in inter prediction of the current block belongs, in a previously defined layer structure in which the combination of one or more horizontal and vertical components of motion vector differences are divided into multiple layers; parsing index data indicating a particular combination within the current layer; inducing a motion vector difference of the current block using the layer data and index data; and inducing the motion vector for the current block by adding the motion vector difference to the motion vector predictor.