The 32-year-old conceded just one goal in the league when City lifted the Women's Super League trophy last season.
She said: "I'm thrilled to extend my contract with Manchester City Women. When I first signed with the club they wanted to become a professional, competitive team that could challenge for titles and I am proud to have been a part of this incredible journey over the last three seasons.
"The support of everyone at the club, from the coaching staff to the fans, has been unbelievable and Manchester City's vision for growing the women's game is as ambitious as ever.
"We've got an exciting season ahead and I can't wait to go after even more success with the team when we kick off the new season in September."