Sega Networks (セガネットワークス) is a Japanese subsidiary of Sega which opened in 2012. It focuses on content for mobile devices such as smartphones and tablets. It became an important division for Sega due to growth of mobile gaming worldwide, especially in Japan where it became the dominant platform. Sega Networks is not a consistent development team, it has an in-house team pulled from all of Sega's development divisions, as well as sometimes partnering with teams that are usually focused on consoles, handhelds and arcades. Also it works with external companies where Sega is joint trademarked with a different company, such as Hortensia Saga. There is also a western division located in Sega of America, called Sega Networks Inc.. Overseas mobile offering over some games which are to be purchased. However, Japan's offering are exclusively free to play.

A sister division of Sega Networks is Online R&D.