Wesley was seen as one of the UK's finest authors after having her first novel published when she was 70.
She died at her home in Totnes, Devon, on Monday.
"
She was someone who started a new wave of writing
"
Toby Eady
Son
The Camomile Lawn, a delicate story of a family's last holiday before World War II, was her most famous work.
It was turned into a television drama starring Felicity Kendal and Jennifer Ehle in 1991.
"She was a deeply feminine woman who wrote about being a woman in a way which had not been done before," her son, literary agent Toby Eady said.
He said she "started a new wave of writing".
Other well-known works included Jumping the Queue, An Imaginative Experience and The Vacillations of Poppy Carew.
Born Mary Aline Mynors Farmar in Berkshire in 1912, Wesley worked for the War Office during World War II.
She wrote two children's books in 1969, and the death of her second husband, journalist Eric Siepmann, in 1970, left her almost penniless.
"
Sixty should be the time to start something new, not put your feet up
"
Mary Wesley
Recent interview
Her first novel, Jumping the Queue, was not published until 1983, and The Camomile Lawn became her first commercial success the following year.
"I have no patience with people who grow old at 60 just because they are entitled to a bus pass," she said in a recent interview.
"Sixty should be the time to start something new, not put your feet up."
One critic described her as "one of the most distinctive voices in English fiction" while others praised her use of "gutsy" heroines who were strong and often shocking.
Her last book, Part of the Scenery, published in 2001, was about her life in Devon and her memories of the area.