Lynda starred opposite Sir David Jason and Ronnie Barker as Nurse Gladys Emmanuel in the hit BBC sitcom, which ran for four series starting in 1976.
She also appeared in the sequel Still Open All Hours when it returned in 2013, and played Auntie Mabel in the 1990s BBC children's programme Come Outside.
A statement to the PA news agency from her agent of nearly 30 years, Donna French, said: "It is with great sadness that we announce the passing of our beloved client Lynda Baron.
"She was a wonderful actress and a great friend.
"Her iconic roles of Nurse Gladys in Open All Hours and Aunt Mabel in Come Outside were loved by all generations.
"Renowned for her leading roles in West End musicals and dramatic productions alike, we have lost a leading light of our world.
"We extend our deepest condolences to her daughter Sarah, her son Morgan and all her family."
Baron also appeared in the ITV sitcom Oh No, It's Selwyn Froggitt, BBC soap EastEnders as Linda Clarke, the mother of Jane Beale, and made appearances in Doctor Who, Last Of The Summer Wine and Dinner Ladies.
She was nominated for a Bafta in 2011 for her role in The Road To Coronation Street on BBC Four, a one-off drama about the early days of the soap, in which she played actress Violet Carson, who portrayed Ena Sharples in the long-running series.