Elisabeth Sophie of Brandenburg (5 April 1674 – 22 November 1748), was a Duchess consort of Courland by marriage to Duke Frederick Casimir Kettler of Courland, a Margravine consort of Brandenburg-Bayreuth by marriage to Christian Ernst, Margrave of Brandenburg-Bayreuth, and a Duchess consort of Saxe-Meiningen by marriage to Ernst Ludwig I, Duke of Saxe-Meiningen.

[1] Elisabeth Sophie was born to Frederick William I, Elector of Brandenburg and his second wife, Duchess Sophia Dorothea of Schleswig-Holstein-Sonderburg-Glücksburg.

The marriage was arranged as an alliance between the two families; in 1703 her brother Albert Frederick was to marry her first husband's daughter, Mary Dorothea.

In January 1701, Elisabeth Sophie left Courland, her son and stepdaughter for her brother's court in Berlin.

She married Christian Ernst, Margrave of Brandenburg-Bayreuth (6 August 1644 – 20 May 1712) on 30 March 1703 in Potsdam.