Princess Margaretha, Mrs. Ambler, (Margaretha Désirée Victoria; born 31 October 1934) is a Swedish princess, the eldest sister of King Carl XVI Gustaf of Sweden and also first cousin of Queen Margrethe II of Denmark.

Margaretha was born on the 31st of October 1934 at Haga Palace in Haga Park, Stockholm as the first child of Prince Gustaf Adolf, Duke of Västerbotten and his wife Princess Sibylla of Saxe-Coburg-Gotha; Paternal granddaughter of Crown Prince Gustaf Adolf of Sweden and his late wife Princess Margaret of Connaught; Maternal granddaughter of Prince Charles Edward, Duke of Saxe-Coburg and Gotha and his wife Princess Victoria Adelaide of Schleswig-Holstein; she was born during the reign of her paternal great-grandfather King Gustav V of Sweden.

Although the eldest child, as a female, she was never heir to the throne according to the Swedish constitution current at the time. She was educated privately at the Haga Palace and then at the Stockholm dressmaking school, Märthaskolan (Martha School).

In the 1950s Margaretha had a relationship with Robin Douglas-Home, a Scottish aristocrat and the nephew of the future Prime Minister of the United Kingdom Alec Douglas-Home. He came to visit her in Sweden, but they never married. There was speculation in the press that this was due to Sibylla forbidding the match, but Margaretha’s nanny and confidante Ingrid Björnberg states categorically in her memoirs that the breakup between the two was caused by Margaretha’s reluctance to enter into an engagement with Douglas-Home.

She met her future husband, the businessman John Ambler, ten years her elder, at a dinner party in the United Kingdom in 1963 and their engagement was announced on 28 February 1964. They were married on 30 June 1964, in Gärdslösa Church, on the island of Öland. The Princess wore a wedding gown from the Stockholm couture school, Märtaskolan, where she had previously been a student, and a traditional wedding crown from Öland.

The couple settled at Chippinghurst Manor in Oxfordshire. As a result of her unequal marriage, she lost her style of Royal Highness and the King gave her the courtesy title of Princess Margaretha, Mrs. Ambler. Under the Swedish constitution of that time, she, as a woman, and her descendants were not eligible to inherit the throne. Thus they still are not.

Margaretha and her husband separated in 1994, but never divorced. He died on 31 May 2008.

In June 1960 Margaretha, along with her first cousin Crown Princess Margrethe of Denmark and her second aunt Princess Astrid of Norway, toured the United States on the occasion of the first transatlantic flight by Scandinavian Airlines. During their visit, the three Scandinavian princesses toured Disneyland and Hollywood[7] and also visited Paramount Pictures in Los Angeles where they met Dean Martin, Jerry Lewis, and Elvis Presley.

Margaretha lives near Chipping Norton, Oxfordshire, in the UK, and does not perform any official engagements on behalf of the royal family.

She takes part in family events as part of the extended royal family, such as: King Carl XVI Gustaf’s 50th birthday celebrations, King Carl XVI Gustaf’s Ruby Jubilee commemorative service, The wedding of her niece Crown Princess Victoria and Daniel Westling, The wedding of her niece Princess Madeleine and Christopher O’Neill, The wedding of her nephew Prince Carl Philip and Sofia Hellqvist, christenings, and funerals

She also used to open the annual Swedish Church Christmas Bazaar in London