The 26-year-old Chelsea midfielder returned to Stamford Bridge from a loan spell at West Ham last season and has established himself as a regular under new Blues boss Antonio Conte.
''I feel very excited. I am delighted to be here for another few years now and to sign a new deal,'' Moses said on the club's official website. ''Now it is time to concentrate on the team and keep working hard to make sure we win games and try to win the Premier League this season. We are having a great season, I am enjoying my football and we have a good manager here that has given every single one of us confidence. I just want to keep on enjoying it and working hard for the team.''