The British number one linked up with Belgian Fissette, who had previously worked with the likes of Kim Clijsters, Simona Halep and Victoria Azarenka, ahead of the 2017 campaign.
Konta said in a statement: “After careful thought and discussion, Wim Fissette and I have mutually decided to end our working relationship.
“Things ended very amicably and I wish Wim all the best. We’ve achieved a lot together and I want to thank him for all his patience, hard work and expertise.
“I will be working with my team over the coming weeks to find the right way forward for me and my tennis. The goal is to get a new coach or coaches in place as soon as possible but the focus will be on making the right decision rather than a quick decision.
“I feel very excited and optimistic about the future and very committed to improving and becoming the best tennis player that I can be.”
The rest of Konta’s coaching staff will remain the same and she will continue to work with hitting partner Andrew Fitzpatrick, strength and conditioning specialist Gill Myburgh, physio Milly Mirkovic and mental coach Elena Sosa.
Under Fissette, she won the biggest title of her career at the Miami Open in April and then reached the semi-finals of Wimbledon to climb to fourth in the world rankings.
But things have soured since with the 26-year-old winning just two matches since her loss to Venus Williams at Wimbledon, losing her last five matches.
That miserable sequence, coupled with a remarkable run of form for France’s Caroline Garcia, saw Konta just miss out on the WTA Finals in Singapore for the second year in a row.
Konta has also been plagued by a foot injury, which saw her pull out of last week’s Hong Kong Open and the Kremlin Cup in Moscow this week, and she has decided not to play again this season.