G-mode Co., Ltd. is a Japanese studio specializing in game content for mobile networks. It became especially known for acquiring the back catalogue of Data East Corporation with more than 40 classic games.

The company currently licenses the content for re-releases of classic games on the Nintendo Wii Virtual Console, GameTap, and mobile games, but also releases of classic games on more modern platforms.

In January 2014, all shares in the company were acquired by ONE-UP Co., Ltd., and on March 2014 the company was merged completely into ONE-UP, with ONE-UP renaming themselves to G-mode.