The couple tied the knot at the Grammy-nominated singer's Palm Springs, California home in August 2014, two months after Lang revealed their engagement on Instagram in June 2014, reported People magazine.
"After much soul searching and consideration we have made the decision to separate as a couple. We are, however, dedicated to remaining friends. There will be no further comment," the couple said in a statement.
Sia and Lang were last pictured together at the Spotify pre-Grammy party in February.