The 39-year-old, who is currently competing in the Tour de France, made the announcement ahead of the penultimate stage with a video posted on his personal and team's social media accounts.
"So tomorrow’s stage will definitely be my last in the Tour de France and after 2021 I will also retire, so the end of the year will be a point at the end of my career," Greipel said.
The German will retire as one of the most successful sprinters of all time, winning 11 stages in the Tour de France during his career, seven stages in the Giro d'Italia and four in the Vuelta a España.
He was a great favourite in Australia as well, winning 18 stages of the Tour Down Under and the race overall twice in 2008 and 2010.
"I’m super happy with what I achieved together with my teammates and the staff around me. I was always happy with the support that I had around. Without my teammates, the staff, and of course my family I wouldn’t have achieved what I have," he added.
"I’m not looking back in anger. I’m looking to the future with a lot of happiness because I can do what I want. I can suffer when I want and of course, spend a lot of time with my family. I wish everyone a good time in the pro peloton. I hope to somehow stay in cycling."
"I’m really thankful for everyone around me in my career. My family, my trainers, and everybody who was part of my career. I’ll see you around. Ciao, ciao."
Greipel moved into the professional ranks with T-Mobile in 2006, and built one of the most consistent sprinting careers ever seen. 158 professional wins, including a run of 12 Grand Tours which included a stage victory.
He moved on the powerful sprinting squad HTC-Highroad for a number of successful seasons, leaving at the end of 2011 with the team trying to share races between him and Mark Cavendish. He moved to Lotto-Soudal and enjoyed the most successful period of his career, claiming team leadership and often the entire team was based around him at the Grand Tours.
Greipel has hinted at the possibility of moving on to a staff position in the Israel Start-Up Nation team, saying when he extended his contract with the team that he would like the opportunity to continue on with the squad in a staff role.
