The world No1 golfer has been with the English coach for three years, but Leadbetter confirmed in a statement on Thursday that they have parted ways.
"These things happen in the world of coaching, whether it's Jurgen Klinsmann with the US NationalSoccer Team or Novak Djokovic who just separated from his coach Boris Becker this week," said Leadbetter in a statement. "This turnover is all part of the coaching business."
Ko began her partnership with Leadbetter in November 2013, when she decided to base herself permanently in the USA to tackle the LPGA tour. It meant she split with former mentor Guy Wilson, who had coached her since she was a five year-old.
"We wish Lydia the very best for the future and know that, going forward, if she is able to withstand the many outside pressures associated with being number one in the world, and if her team keep their expectations realistic, then she can go on to even bigger and better things," added Leadbetter.
Ko also split with her caddy Jason Hamilton in October, after a partnership which had yielded 10 titles, including two majors.
The 19-year-old has endured a difficult period since the Rio Olympics, not posting a top 10 finish in five tournaments before the season ending CME Group Tour Championship.
