Babara has played the part of Peggy Mitchell the landlady of the Queen Vic for 15 years and has been a central character in the soap.
She say she want to leave the soap to spend time where her Husband Scott Mitchell who is 26 years her junior.
"I'll be so sad to leave Peggy behind. EastEnders has been wonderful to me and it's no secret that it changed my life all of those years ago," she said.
She added that Peggy has been a "wonderful character to play", and singled out showing the Queen around the set of EastEnders as "something that will stay with me forever".
"I'm looking forward to the future and I suppose when all's said and done, I should spend a bit more time with my old man, as he's not getting any younger."
Windsor's agent Barry Burnett told BBC News that the star had no intention of retiring from showbusiness.
"Oh no, absolutely not, can you imagine that? Anyone who knows Barbara knows what she's like," he said.
EastEnders executive producer Diederick Santer described Windsor's character as "truly iconic".
"Barbara has contributed so much to EastEnders over the last 15 years, plus countless episodes, and countless amazing storylines.
"She has made the Mitchells the premiere family of British soap," he added.
"I so much enjoy working with her - catching up with the gossip, listening to her stories, talking about the show, benefiting from her advice, and most importantly revelling in her powerful, funny, passionate performances.
"All of us at EastEnders - and our audience - are going to miss her hugely."
