Diana, Princess of Wales (born Diana Frances Spencer; 1 July 1961 – 31 August 1997), was a member of the British royal family. She was the first wife of Charles III (then Prince of Wales) and mother of Princes William and Harry. Her activism and glamour, which made her an international icon, earned her enduring popularity.

Diana was born into the British nobility and grew up close to the royal family, living at Park House on their Sandringham estate. In 1981, while working as a nursery teacher's assistant, she became engaged to Charles, the eldest son of Queen Elizabeth II. Their wedding took place at St Paul's Cathedral in July 1981 and made her Princess of Wales, a role in which she was enthusiastically received by the public. The couple had two sons, William and Harry, who were then respectively second and third in the line of succession to the British throne. Diana's marriage to Charles suffered due to their incompatibility and extramarital affairs. They separated in 1992, soon after the breakdown of their relationship became public knowledge. Their marital difficulties were widely publicised, and the couple divorced in 1996.

As Princess of Wales, Diana undertook royal duties on behalf of the Queen and represented her at functions across the Commonwealth realms. She was celebrated in the media for her beauty, style, charm, and later, her unconventional approach to charity work. Her patronages were initially centred on children and the elderly, but she later became known for her involvement in two particular campaigns: one involved the social attitudes towards and the acceptance of AIDS patients, and the other for the removal of landmines, promoted through the International Red Cross. She also raised awareness and advocated for ways to help people affected by cancer and mental illness. Diana was initially noted for her shyness, but her charisma and friendliness endeared her to the public and helped her reputation survive the public collapse of her marriage. Considered photogenic, she was regarded as a fashion icon.

In August 1997, Diana died after a car crash in Paris; the incident led to extensive public mourning and global media attention. An inquest returned a verdict of unlawful killing due to gross negligence by a driver and the paparazzi pursuing her as found in Operation Paget, an investigation by the Metropolitan Police. Her legacy has had a significant effect on the royal family and British society.

Diana Frances Spencer was born on 1 July 1961, the fourth of five children of John Spencer, Viscount Althorp (1924–1992), and Frances Spencer, Viscountess Althorp (née Roche; 1936–2004). She was delivered at Park House, Sandringham, Norfolk. The Spencer family had been closely allied with the British royal family for several generations; her grandmothers, Cynthia Spencer, Countess Spencer, and Ruth Roche, Baroness Fermoy, had served as ladies-in-waiting to Queen Elizabeth The Queen Mother. Her parents were hoping for a boy to carry on the family line, and no name was chosen for a week until they settled on Diana Frances after her mother and Lady Diana Spencer, a many-times-great-aunt who was also a prospective Princess of Wales as a potential bride for Frederick, Prince of Wales. Within the family, she was also known informally as "Duch", a reference to her duchess-like attitude in childhood.

On 30 August 1961, Diana was baptised at St. Mary Magdalene Church, Sandringham. She grew up with three siblings: Sarah, Jane, and Charles. Her infant brother, John, died shortly after his birth one year before Diana was born. The desire for an heir added strain to her parents' marriage, and Lady Althorp was sent to Harley Street clinics in London to determine the cause of the "problem". The experience was described as "humiliating" by Diana's younger brother, Charles: "It was a dreadful time for my parents and probably the root of their divorce because I don't think they ever got over it". Diana grew up in Park House, situated on the Sandringham estate. The family leased the house from its owner, Queen Elizabeth II, whom Diana called "Aunt Lilibet" since childhood. The royal family frequently holidayed at the neighbouring Sandringham House, and Diana played with Princes Andrew and Edward.

Diana was seven years old when her parents divorced. Her mother later began a relationship with Peter Shand Kydd and married him in 1969. Diana lived with her mother in London during her parents' separation in 1967, but during that year's Christmas holidays, Lord Althorp refused to let his daughter return to London with Lady Althorp. Shortly afterwards, he won custody of Diana with support from his former mother-in-law, Lady Fermoy. In 1976, Lord Althorp married Raine, Countess of Dartmouth. Diana's relationship with her stepmother was particularly bad. She resented Raine, whom she called a "bully". On one occasion Diana pushed her down the stairs. She later described her childhood as "very unhappy" and "very unstable, the whole thing". She became known as Lady Diana after her father later inherited the title of Earl Spencer in 1975, at which point her father moved the entire family from Park House to Althorp, the Spencer seat in Northamptonshire.

Diana was initially home-schooled under the supervision of her governess, Gertrude Allen. She began her formal education at Silfield Private School in King's Lynn, Norfolk, and moved to Riddlesworth Hall School, an all-girls boarding school near Thetford, when she was nine. She joined her sisters at West Heath Girls' School in Sevenoaks, Kent, in 1973. She did not perform well academically, failing her O-levels twice. Her outstanding community spirit was recognised with an award from West Heath. She left West Heath when she was sixteen. Her brother Charles recalls her as being quite shy up until that time. She demonstrated musical ability as a skilled pianist. She also excelled in swimming and diving, and studied ballet and tap dance.