The 'Wild' singer announced on Twitter that she has given up her coaching role as her music career "has to take priority".
"I've absolutely loved my time on The Voice and I hope everyone saw and knows how passionately I felt about the show," she began.
"However, I can't wait to promote my new record around the world and that has to take priority.
"I shall be keeping a very close eye on series three, showing my support in every way I can and really hope in some way that I can be part of the show."
Mark Linsey, BBC Controller of Entertainment Commissioning, thanked Jessie J for her time on The Voice and announced that bosses "will now start the search for a new coach".
"We're so sorry to see Jessie go as she's been an exceptional coach on, and advocate for, The Voice, but we totally support her decision to leave due to touring commitments overseas," he said.
"We very much hope that Jessie will remain part of the show and come back and perform for us next series. In the meantime, we will now start the search for a new coach."
The official Voice UK Twitter account later read: "Yes, it's true. After being a redonkulously incredible coach for two series of #TheVoiceUK, @jessiej has left the building (and her chair).
"Despite the sniffles, we wish @jessiej lots of love, luck and bigups and we look forward to seeing her tweets about series 3. #TheVoiceUK...#ByeJessieJ #theVOICEuk."
It is not yet known whether will.i.am, Sir Tom Jones and Danny O'Donoghue will return to The Voice UK for a third series.
Photo gallery - Jessie J's career in pictures: