Buckingham Palace said that Queen Elizabeth II, Margaret's sister, had been told that he died.
"The Earl of Snowdon died peacefully at home on 13th January 2017," said Camera Press, the photo agency with which he worked.
One of the country's most famous photographers, Snowdon was one of the few top-echelon royals to hold down an outside job after he married the queen's sister in 1960, and his professional reputation grew steadily.
Margaret died in 2002.
Snowdon was admired for his discretion, never speaking with the media about the breakup of the marriage in 1978, and rejecting offers to write a book about it. But over time a number of details about his complicated love life emerged.
Born Antony Armstrong-Jones, he was a slightly bohemian member of London's smart set and an established society photographer when he and the queen's sister surprised the country with their engagement in February 1960.
They had met at a London party and managed to keep their courtship a secret in the months that followed, despite intense interest in Margaret's romantic life.
Unconventional, artistic and not nearly as wealthy as Margaret's other suitors, Armstrong-Jones lived in a studio in west London and did his own cooking. He was certainly not seen by the public and press as a royal prospect.
The "Jones Boy" married the high-spirited Margaret at Westminster Abbey on May 6, 1960, in the first royal wedding to be televised. Whatever doubts the country might have had about his suitability were swept aside by general relief that Margaret had, at last, found love. It had been five years since her widely publicized decision to end her romance with divorced war hero Peter Townsend after pressure from church leaders, political figures and her own family.
Armstrong-Jones was named the Earl of Snowdon in October 1961, in time to give a title to their first child, David, Viscount Linley, born the following month. Linley became a successful furniture designer. His sister, Lady Sarah, born in May 1964, became a painter.
Margaret, unlike most of the royal family, shared her husband's interest in the arts, and the two moved in a circle of creative people at a time when "swinging London" gained a worldwide reputation for music, clothes, films and clubs.
In 1969, Snowdon designed the setting for the investiture of Prince Charles as Prince of Wales at Caernarvon Castle in Wales.
Snowdon was born March 7, 1930, the son of lawyer Ronald Armstrong-Jones and Anne Messel, sister of celebrated stage designer Oliver Messel.
Snowdon's first exposure to the world of celebrity came as a teenager when his uncle Oliver Messel brought Noel Coward and Marlene Dietrich to the hospital to sing to him after he was stricken with polio.
Snowdon was educated at Eton and studied architecture at Cambridge University, where he failed his final exams.
He did an apprenticeship with Baron, the leading society photographer of the day, then set himself up as a theatrical photographer. By the late 1950s he was doing a considerable amount of work for fashion magazines.
He had a sense of humor and engaging manner that put his subjects at ease, and he brought a new informality to portraits of the royal family.
By the early 1970s, Snowdon's marriage to Margaret was beset by rumors of infidelity. They separated in 1976 and quietly divorced in 1978.
Snowdon married Lucy Lindsay Hogg, and had a daughter, Frances, in 1979. They divorced in 2000.
Margaret did not remarry, and she died following a stroke in 2002.
In the 1990s, two relationships Snowdon had with other women became public.
After the suicide of 55-year-old journalist Ann Hills in 1997, it was revealed that she had known Snowdon for 20 years, had been a longtime lover and had remained a close friend.
In April 1998, journalist Melanie Cable-Alexander gave birth to a son, Jasper, and said Snowdon was the father. He did not deny it.
In later years, Snowdon was troubled by the effects of polio, which left him with a slight limp, and he had difficulty standing for any length of time. He endowed a fund that provides scholarships for disabled students.
Snowdon remained a favorite photographer of the queen long after his marriage to her sister ended in rancor, and he took many portraits of her. Diana, Princess of Wales, was another frequent subject.
Snowdon received a rare honor in 2001 when the National Portrait Gallery presented a retrospective of his work, with more than 180 examples exhibited. Yet he remained modest about his skills.
"If I had a style I'd consider that one of my failings," he said "The person you're photographing is the important person. The photographer should be a chameleon."
He produced 14 photographic books and made seven television documentaries on a wide range of social issues. The first, "Don't Count the Candles," about old age, won two Emmy awards in 1968.
He designed the Snowdon aviary for the London Zoo. One of his favorite projects, it is an aluminum tension structure and one of the zoo's biggest attractions.
(AP)