Wilhelmina von Hessen-Kassel (25 February 1726 – 8 October 1808) was a Prussian princess, married to prince Henry of Prussia.
Wilhelmina was the daughter of prince Maximilian of Hesse-Kassel and Friederike Charlotte of Hessen-Darmstadt and the niece of landgrave William VIII of Hesse-Kassel and king Frederick of Sweden. She was introduced to Henry when he visited Kassel in 1751 and was married to him 25 June 1752. Wilhelmina was described as a charming beauty. Wilhelmina and Henry had their own court and lived at Schloss Rheinsberg and Berlin. Wilhelmina had no children with Henry, who was reported to pay more attention to his male friends than to her. The couple separated in 1766 after an alleged affair on Wilhelmina's side. After the separation, she lived at Palais Unter den Linden in Berlin, where she was served by successive members of the von Blumenthal family (Amalia, Charlotte, Marie-Thérèse and Leopoldine) as ladies-in-waiting .
The Swedish Princess Hedwig Elizabeth Charlotte of Holstein-Gottorp described her at the time of her visit in 1798:
She was a tall and handsome lady with a well kept figure, though very thin, and you can still see how remarkably beautiful she was in her youth. Her eyes are big and lively though somewhat protruding, and with a restless look. She is witty and literal, but as a consequence of her age, she sometimes talks of several subjects at the same time. Her manners are regal, and she represents perfectly, and was additionally very polite and toward me very pleasant.
She was one of the few members of the royal house to remain in Berlin during the French occupation in 1806. While most of the royal family left, reportedly because of the anti-Napoleonic critic they had expressed, and the members of the royal court either followed them or left the capital for their country estates, Wilhelmina remained with Prince Augustus Ferdinand of Prussia and his consort Margravine Elisabeth Louise of Brandenburg-Schwedt because of "their high age" as well as Princess Augusta of Prussia, who was pregnant at the time.