Mata Hari was the stage name of Margaretha Geertruida "Grietje" Zelle (7 August 1876, Leeuwarden – 15 October 1917, Vincennes), a Frisian (Dutch) exotic dancer and courtesan who was executed by firing squad for espionage during World War I.

Margaretha Geertruida Zelle was born in Leeuwarden, Friesland in the Netherlands, the eldest of four children of Adam Zelle (2 October, 1840, Leeuwarden - 13 March, 1910, Amsterdam) and first wife (m. Franeker, 4 June, 1873) Antje van der Meulen (21 April, 1842, Franeker - 9 May, 1891, Leeuwarden). She had two brothers and one sister. Her father owned a hat store, made successful investments in the oil industry, and became affluent enough to give Margaretha a lavish early childhood. Thus, Margaretha attended only exclusive schools until age 13.

However, Margaretha's father went bankrupt in 1889, her parents divorced soon thereafter, and Margaretha's mother died in 1891. Her father remarried in Amsterdam on 9 February, 1893 Susanna Catharina ten Hoove (11 March, 1844, Amsterdam - 1 December, 1913, Amsterdam), with whom he had no children. The family had come apart and she moved to live with her godfather, Heer Visser, at Sneek. At Leiden, she studied to be a kindergarten teacher, but when the headmaster began to flirt with her conspicuously, she was removed from the institution by her offended godfather. After only a few months, she fled to her uncle's home in The Hague.