A method of encoding a motion vector includes: selecting one of a plurality of predicted candidate motion vector sets by using motion information of neighboring blocks of a current block; selecting one of predicted candidate motion vectors within a selected predicted candidate motion vector set, as a predicted motion vector; encoding a differential motion vector representing a difference between a current motion vector or motion vector of the current block and a selected predicted motion vector; and encoding a predicted motion vector index indicating the selected predicted motion vector. As a motion vector is encoded after selecting an efficient predicted candidate motion vector set, the size of a differential vector to be encoded can be reduced without necessarily encoding additional information to indicate which set of predicted candidate motion vectors has been selected, resulting in improved compression efficiency of motion vectors and in turn the improved video compression efficiency.