Landgravine Elisabeth Henriëtte von Hessen-Kassel (18 November 1661 – 7 July 1683) was the daughter of William VI, Landgrave of Hesse-Kassel and Hedwig Sophia of Brandenburg (1623–1683) and electoral princess of Brandenburg through her marriage to Frederick I of Prussia.^[1]

Elisabeth Henriëtte was born in Kassel, Germany on 18 November 1661 to William VI, Landgrave of Hesse-Kassel.^[1] She was the youngest of seven; siblings included Queen Charlotte Amalie, William VII, Luise, Charles I, Philip, and George.^[2] She suffered from an unknown illness in 1677 that her mother treated with the milk cure, wherein a teenage Elisabeth suckled from a wet nurse for three weeks and eventually recovered.^[3] Years later, on 13 August 1679, she married her cousin, Frederick, Prince Elector of Brandenburg, in Potsdam^[1] after his plan to marry a sister of Holy Roman Emperor Leopold I fell through.^{[citation needed]} They held court in Köpenick Palace in a district of Berlin.^[1] On 29 September 1680, Luise Dorothea Sophie, the couple's only child, was born.^[1] Luise Dorothea later married Frederick I of Sweden, her first cousin, and became the electoral princess of Hesse-Kassel before dying in childbirth in 1705 at age 25.^[4][5]

Elisabeth Henriëtte died on 7 July 1683 at age 21 from smallpox.^[1][6] Frederick accused his stepmother Dorothea of poisoning her but this was found to be untrue via investigation.^[1] She is buried at Berlin Cathedral with Frederick and his second wife Sophia Charlotte.^[7]