Alonso won F1 titles in 2005 and 2006 while driving for Renault but switched to McLaren for the 2007 season and finished tied for second in drivers’ standings, 1 point behind Ferrari’s Kimi Raikkonen.
"Since I was a boy I had always wanted to drive for McLaren, but sometimes in life things do not work out," said Alonso in a statement. "I continue to believe that McLaren is a great team. Yes, we have had our ups and downs during the season, which has made it extra challenging for all of us, and it is not a secret that I never really felt at home."
The decision for Alonso, who had two years left on his contract, to leave McLaren was said to be mutual.
"He is a great driver but for some reason the combination of Vodafone McLaren Mercedes and Fernando has not really worked out and in the end we reached a stage where none of us could find a way to move forward," said McLaren team chairman Ron Dennis.
Benedict Cumberbatch's dramatic reading of R. Kelly lyrics is just what you need
Beyonce flaunts bikini body, Blue Ivy in vacation pics