Klitschko confirmed the news with a statement on his website which reads,
“I deliberately took a few weeks to make my decision, to make sure I had enough distance from the fight at Wembley Stadium.
“As an amateur and a professional boxer, I have achieved everything I dreamed of, and now I want to start my second career after sports.I would have never imagined that I would have such a long and incredibly successful boxing career. I’m very thankful for this.
“Thanks to everyone who has always supported me. Especially my family, my team and my many fans.”
His retirement dashes a mooted blockbuster rematch with Joshua possibly in Las Vegas in November.
Klitschko, who won super-heavyweight gold at the 1996 Atlanta Olympic Games, held the unified title from 2006-2015 before losing to Tyson Fury in 2015. He bows out with a record of 64 wins and five defeats.