An image encoding/decoding method and apparatus for performing template matching-based intra prediction are provided. An image decoding method may comprise deriving a first intra-prediction mode for a current block, generating a first intra-prediction block corresponding to the first intra-prediction mode, deriving a second intra-prediction mode for the current block, generating a second intra-prediction block corresponding to the second intra-prediction mode, and generating a final intra-prediction block by using a weighted sum of the first intra-prediction block and the second intra-prediction block.