The British author died peacefully at her London home in the early hours of this morning, a spokesman said.
Born in Persia (modern day Iran) in 1919, Ms Lessing grew up in Southern Rhodesia before emigrating to London after the Second World War with the manuscript of her first novel, The Grass Is Singing, in her suitcase.
It was published in 1950 and across the course of her life she produced 54 further works, including poetry, two operas, short stories, plays and non-fiction.
In 2007, she became the oldest recipient of the Nobel Prize, aged 88, and only the 11th woman to win the award.
Jonathan Clowes, her long time friend and agent, said today that he was greatly saddened by the news.
He said: "She was a wonderful writer with a fascinating and original mind; it was a privilege to work for her and we shall miss her immensely."
The writer is survived by her daughter Jean and grand-daughters Anna and Susannah. Her family has asked for privacy at this time.
Tributes to the late Ms Lessing have poured in from friends and colleagues, who have heralded her novels as "handbooks" to a generation or readers.
Nicholas Pearson, her editor at HarperCollins, said: "Doris's long life and career was a great gift to world literature.
"She wrote across a variety of genres and made an enormous cultural impact. Probably she'll be most remembered for The Golden Notebook which became a handbook to a whole generation, but her many books have spoken to us in so many various ways.
"Doris has been called a visionary and, to be in her company, which was a privilege I had as her editor towards the end of her writing life, was to experience something of that.
"Even in very old age she was always intellectually restless, reinventing herself, curious about the changing world around us, always completely inspirational. We'll miss her hugely."
The publishing house's UK chief executive, Charlie Redmayne, added: "Doris Lessing was one of the great writers of our age. She was a compelling storyteller with a fierce intellect and a warm heart who was not afraid to fight for what she believed in. It was an honour for HarperCollins to publish her."
Justifying her Nobel Prize six years ago, the Academy described the author as an "epicist of the female experience, who with scepticism, fire and visionary power has subjected a divided civilisation to scrutiny".
In response, Ms Lessing famously famously poked fun at the judges for snubbing her work 40 years earlier. She joked: "So now they've decided they're going to give it to me. So why? I mean, why do they like me any better now than they did then?"
Lessing's youthful background in Africa induced her to write about the clash of cultures and the injustices of racial inequality.
Her early novels, published during the 1950s and 1960s, decried the dispossession of black Africans by white colonials and exposed what she regarded as the sterility of the white culture in southern Africa.
So fierce were her views that in 1956 she was declared a prohibited alien in both Southern Rhodesia (now Zimbabwe) and South Africa, and attacked for being "unfeminine" in her depiction of female anger and aggression
In the 1970s and 1980s, she embarked on "inner-space fiction", books dealing with cosmic fantasies, dreamscapes and other dimensions including science fiction that contemplates higher planes of existence.
It is a body of work, standing finally at more than 50 novels, poetic works, plays and more, that in 2007 earned her the Nobel Prize for Literature, the 11th woman and oldest person to win the award.
In 2001, she was awarded the David Cohen Price for a lifetime achievement in British Literature.
Doris Lessing was born Doris May Tayler in Persia, now Iran, but the family soon moved to Southern Rhodesia where her father's attempt to get rich through maize farming came to nothing.
She described her childhood as an uneven mix of some pleasure and much pain, with a mother who imposed strict rules and hygiene requirements. She was sent to a convent, where nuns terrified the children with stories of hell and damnation. After that she attended an all-girls high school in Salisbury (now Harare) from which she dropped out at the age of 13. That was the end of her formal education.
She left home aged 15 and worked as a nursemaid while her employer's brother-in-law crept into her bed at night and gave her inept kisses.
She said that at this stage she was in "a fever of erotic longing", frustrated by her clumsy suitor. By now she had started to write.
In 1937, she moved to Salisbury and worked as a telephone operator. She married at the age of 19 to Frank Wisdom and they had two children, before leaving her family.
Lessing was then drawn into a group of Communists and married a central member, Gottfried Lessing, with whom she had a son. But during the postwar years she became disillusioned with Communism and left the movement in 1954, by which time she was living in London.
She published her first novel in 1949, The Grass is Singing, and became a professional writer. Books then simply poured out of her, most of them touching on social ills and deprivation.
Lessing also wrote several non-fiction works, including books about cats, a love since childhood. Her Under My Skin: Volume One of My Autobiography to 1949 appeared in 1995 and received the James Tait Black Prize for best biography.
In that year she received an honorary degree from Harvard University, and visited her daughter and grand-children in South Africa as well as to promote her autobiography.
It was her first visit since being forcibly removed in 1956 for her political views. She was now welcomed and acclaimed for the very topics for which she was banished 40 years earlier.
She was appointed a Companion of Honour in the 2000 New Year Honours List. At the time she disclosed she had turned down the offer of becoming a Dame of the British Empire "because there is no British Empire".