Ernst Ludwig, Grand Duke of Hesse and by Rhine (25 November 1868 Darmstadt - 9 October 1937 Schloß Wolfsgarten) was the reigning Grand Duke of Hesse from 1892 to 1918. The son of Grand Duke Ludwig IV and Princess Alice of the United Kingdom, daughter of Queen Victoria. He was brother to Empress Alexandra of Russia.

Ernst Ludwig succeeded his father as Grand Duke of Hesse and by Rhine in 1892 and married his first cousin, Princess Victoria Melita of Saxe-Coburg and Gotha , two years later, but the marriage was not a happy one. Ernst Ludwig was himself a homosexual, and the two divorced in 1901, having had only one child, a daughter, who died shortly thereafter in an accident. Ernst Ludwig remarried in 1905 to Princess Eleonore of Solms-Braunfels . Ernst Ludwig served in the German military during the First World War, and was forced to abdicate along with the other German ruling princes at the end of the war in 1918. He remained in Germany thereafter, and died in 1937.