The 18-year-old has made his way through the youth academy ranks at Chelsea and currently has 17 first-team appearances under his belt.
"It is what I wished for when I was a kid and hopefully I will spend my career at Chelsea," the club’s official website quotes McEachran as saying.
"This season my target is just to play more minutes. Hopefully I will play more games and keep improving."
The midfielder won the FA Youth Cup with the Premier league side in 2010 and was selected in the squad for the England Under-19 friendly against Germany.
Teammate Ryan Bertrand has also committed to Chelsea with a new four-year deal.