The actress died at her home in Surrey on Sunday with her family by her side.
An EastEnders spokeswoman said: “We are deeply saddened to announce that our beloved June Brown, OBE, MBE, sadly passed away last night.
“There are not enough words to describe how much June was loved and adored by everyone at EastEnders, her loving warmth, wit and great humour will never be forgotten.
“June created one of the most iconic characters in Dot Cotton, not just in soap but in British television, and having appeared in 2,884 episodes, June’s remarkable performances created some of EastEnders’ finest moments.
“We send all our love and deepest sympathies to June’s family and friends. A very bright light has gone out at EastEnders today but we shall all be raising a sweet sherry in June’s memory.
“Rest in peace, our dearest June. You will never be forgotten.”
A statement from Brown’s family said: “We are deeply saddened to announce our beloved mother, June, passed away very peacefully at her home in Surrey on Sunday evening, with her family by her side.
“We would kindly ask that our privacy is respected at this very difficult time.”
The actress’s 35-year run as the Albert Square mainstay began in 1985. before she left the show in 2020.
Brown was perhaps EastEnders’ best-known star and larger-than-life Dot was known for her devout Christian faith and hypochondria, as well as her endless cigarette addiction.
The veteran actress, who had a long career in television and theatre, arrived on Albert Square shortly after the soap began in 1985, and aside from a break between 1993 and 1997, was a regular for more than three decades.
On January 31 2008 she single-handedly starred in an episode called Pretty Baby, in which she spoke to a cassette recorder about her life so that her husband could listen to it as he lay in hospital following a stroke.
Brown served in the Women’s Royal Naval Service at the end of the Second World War, and then left to train at London’s Old Vic Theatre School in Lambeth.
Before joining EastEnders she had roles in Coronation Street, Doctor Who, Minder and The Bill, as well as costume dramas The Duchess Of Duke Street and Oliver Twist.
After joining Albert Square she also starred in comedy Ain’t Misbehavin in 1997, and played Nanny Slagg in the BBC’s production of Gormenghast in 2000.
She announced the bombshell news of her exit from EastEnders in 2020 with little fanfare, revealing her decision on a podcast with a former co-star.
Dot had not featured in the soap for a month, when she left a voicemail for Sonia Fowler saying she had moved to Ireland.
At the time an EastEnders’ spokesman said the door remained open for a comeback, appearing to leave the decision in Brown’s hands.
Some of Dot’s biggest storylines explored controversial issues such as euthanasia, cancer and homophobia.
Her marriage to Jim Branning, played by John Bardon, was popular among fans – while she was also mother to the notorious criminal Nick Cotton, played by John Altman.
Brown won several awards for her portrayal of Dot, including a lifetime achievement honour at the 2005 British Soap Awards.
In 2009, she was nominated for the best actress prize at the TV Baftas for her standalone episode of the soap.
In December 2021 Brown was made an OBE in the New Year Honours, as she was recognised for services to drama and to charity.
She was previously made an MBE in the Queen’s Birthday Honours in 2008 for services to drama and charity.
Brown married her first husband, John Garley, in 1950.
After his death she married actor Robert Arnold in 1958 and had six children with him.