Hayes, who has been in charge of the Blues for nine years, has enjoyed remarkable success over the past decade.
She has won 10 major trophies with Chelsea, including four Women’s Super League titles and two FA Cups.
Hayes also led Chelsea to the final of the Champions League last season, where they were beaten by Barcelona.
“Everyone knows what this club means to me,” said Hayes after signing a new long-term deal on Friday.
“The work we’ve done together over the last nine years has been hugely rewarding, full of growth of the women’s game, accompanied with winning, which is one of the club’s key values.
“I really look forward to keep building on the successes we’ve already achieved and I’m delighted to have extended further.
Chelsea director, Marina Granovskaia, added: “We are delighted Emma has committed to stay at Chelsea.
“History speaks for itself, and we are really proud of what she has achieved in the past nine years, not just at the club, but also for the growth of the women’s game. It is phenomenal and a real credit to Emma for her continued passion, hard work and dedication to the sport.
“We have no doubt there’s more exciting times to come and look forward to watching her take Chelsea Women to even greater heights in the years to come.”