The couple revealed the break-up in a statement on Paltrow's lifestyle website.
"It is with hearts full of sadness that we have decided to separate," the couple said on Goop.com, in a post entitled "Conscious Uncoupling."
"We have come to the conclusion that while we love each other very much we will remain separate. We are, however, and always will be a family, and in many ways we are closer than we have ever been," they added.
Paltrow, 41, who won a Best Actress Academy Award for Shakespeare in Love and British singer Martin, 37, were married in December 2003, and have two children, Apple and Moses.
The notoriously private couple, who avoid being photographed together in public, will "consciously uncouple and coparent" their children, the couple said