Gummer's representative confirmed the break-up to People, the magazine reported Saturday.
Gummer, 29, and Walker, 30, met in 2008 while they were both performing in the Broadway play "Dangerous Liaisons."
They got engaged in October 2009 and tied the knot in July 2011 at Gummer's family estate in Connecticut.
Aaron Carter is still in love with Hilary Duff
Boston schools pull out free condoms over wrapping complaints