Cook, 32, has led the English cricket team through a record 59 Tests and skippered them to Ashes victories in 2013 and 2015.
However, during the 4-0 Test series defeat in India he admitted to having "questions" over his role, and has ended a reign that began in 2012.
"Stepping down has been an incredibly hard decision but I know this is the correct decision for me and at the right time for the team," said Cook.
"Playing for England really is a privilege and I hope to carry on as a Test player, making a full contribution and helping the next England captain and the team however I can."
(Source : BBC News)