The 26-year-old - formerly of Fulham, Crystal Palace and Swindon Town - still had two years remaining on his previous deal, signed when he joined on a free from the Robins in 2015.
During his first season, Foderingham helped Gers secure promotion back to the Scottish Premiership after a four-year absence and recently passed the 100-appearances milestone for the club.
"I am very happy. Since I have joined the club I have remained the number one and I have had great times at the football club. I was keen to extend my stay and it made sense for both parties," Foderingham told the Rangers website.
"I am just happy playing my football here, I had two years left on my deal and the club approached me and said they wanted to extend it. Of course I had no reservations about that and I am happy to sign. If I am being totally honest I had options to leave this summer but in my mind I always wanted to stay at this football club, the club said they wanted to keep me here and I am pleased they did.
"I joined this football club to play in Europe, to be on the big stage and I want to be there when the club returns. All the boys here want to be playing in Europe and at the highest level possible – I think I can achieve that at Rangers."
Rangers manager Pedro Caixinha added: "Wes is our number one and we are glad that he has signed his agreement with the club. He still isn't at the age where goalkeepers are usually mature, so he still has room to grow and get that maturity."
Gers are currently third in the Scottish Premiership after taking 11 points from their first six league games of the season.