The 25-year-old will remain at Upton Park until the summer of 2020, with the option of a further two years.
The left-back joined from Ipswich Town last summer and played every minute of their Premier League campaign in 2014/15.
In his debut season, he won the Players??? Player of the Season award and also the Hammer of the Year prize.
Cresswell told West Ham TV: ???It’s exciting times for me to pen a new deal at West Ham
???It’s nice to finally commit my future to West Ham.??I was at Ipswich 12 months ago and when West Ham came in for me there was only one place for me.
???I jumped straight in the car, down the A12 and signed for West Ham. These are exciting times.???