The 26-year-old, who started out as a midfielder, has become a key player for Chelsea this season, excelling in a wing-back role since manager Antonio Conte switched to a 3-4-3 formation in October.
Moses, who joined the club in 2012, has spent most of his career out on loan, with spells at Liverpool, Stoke City and West Ham United, but has made 28 appearances in all competitions this season under Conte, scoring four times.
“We’re having a great season, I’m enjoying my football and we have a good manager here that has given every single one of us confidence,” Moses told the club’s website. (www.chelseafc.com)
“I just want to keep on enjoying it and working hard for the team.”
Chelsea are 10 points clear at the top of the table and visit ninth-placed West Ham United on Monday.