The 33-year-old scored 36 tries in 78 internationals, putting him second behind Rory Underwood on England's list of all-time leading try scorers.
"Words can't describe the journey that I've been on so I won't try to put it into words," May said in a statement on englandrugby.com.
"At this point in time all I want to say from the bottom of my heart is a huge thank you to everybody who has been a part of this journey with me.
"It's an honour and a dream to represent my country and although I won't be out there on the pitch anymore physically, I will always feel connected to this team in spirit."
May, who plays for Gloucester in the English Premiership, was a member of Steve Borthwick's squad at the World Cup in France, but did not appear in Friday's third-place play-off victory against Argentina.
