Elisabeth Christine Ulrike of Brunswick-Wolfenbüttel (Elisabeth Christine Ulrike; 8 November 1746 – 18 February 1840), was the first wife of Crown Prince Frederick William, her cousin and the future king Frederick William II of Prussia.

She was the seventh child and third daughter of Charles I, Duke of Brunswick-Lüneburg and Princess Philippine Charlotte of Prussia, the sister of Frederick the Great. She held the rank of Duchess in Brunswick with the style of Her Serene Highness Princess Elisabeth Christine.

She was selected as a suitable bride for the heir of the throne of Prussia for his uncle, the childless King, who considered her particularly witty and beautiful. The marriage ceremony between Elisabeth Christine and Crown Prince Frederick William was originally planned to take place at Charlottenburg Palace's Chapel, but at the end took place on 14 July 1765, on the family country estate Schloss Salzdahlum.

Soon it became clear the couple was not happy with each other. King Frederick had hoped that the marriage would lead to the production of an heir, but instead noticed that Frederick William neglected his wife and was unfaithful to her on a daily basis with a series of dancers and actresses. When their first child proved to be a girl (Princess Frederica Charlotte, born 7 May 1767; she later married Prince Frederick, Duke of York and Albany), their relationship deteriorated.

Wounded by her husband's neglect and infidelity, the Crown Princess began to have affairs with young officers of the Potsdam Guard. In a letter wrote to his sister (and Elisabeth Christine's mother) Philippine Charlotte, the concerned King says:

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