The British actress, 41, has been playing market stall holder Bianca Butcher on the BBC soap for more than two decades.
Palmer’s post-EastEnders plans remain unclear but Dominic Treadwell-Collins, the show’s executive producer, confirmed that her hot-tempered character will not be killed off.
“We are so sad that Patsy has decided to leave us but completely understand that it’s the right time for her,” he said.
“Bianca won’t be leaving Albert Square until the autumn, so there’s still a lot more to come from her on screen this year – and the door will be left wide open for her return. We won’t be getting rid of Bianca’s puffer jacket just yet.”
Palmer’s spokesperson released a statement about the news, saying that she was “really sad to be leaving the show (…) but knows it’s the right decision at this time in her life”.
Palmer's Bianca is best known for her frustrated cries of “Rickaaaay!” when addressing her first husband, played by Sid Owen, who incidentally also left EastEnders to pursue work in Hollywood .
Other dramas have included her children being taken into care and her boyfriend Tony abusing her adoptive daughter.
Palmer left EastEnders once before in 1999, before returning for a one-off episode in 2002 and making a full comeback in 2008.