Gilbert helped to coach Gauff to her first Grand Slam trophy in New York last year but the player was unable to retain her title after disappointing early departures from the US Open tune-up tournaments in Toronto and Cincinnati.
"Thanks to @CocoGauff and the entire team for an absolutely amazing summer run in 2023 and for 14 months of incredible team effort," Gilbert, who got to number four in the world during a 13-year playing career, said on X.
"Coco, at just 20 years young, your future is incredibly bright, and I wish you nothing but continued success ahead. I’m excited for the next chapter in my coaching career."
Gauff thanked her former coach in a social media post later on Wednesday.
"We had an incredible run and I wish you all the best in the future!" she wrote on X.
Gauff followed up her major breakthrough in Flushing Meadows with semi-final berths at the Australian Open and French Open this year.
But there were clear signs of friction between her and fellow American Gilbert at Wimbledon, where she shouted in frustration at him during her fourth-round defeat against American Emma Navarro.
