| Ernest of Hesse-Philippsthal | |
| House: | House of Hesse |
| Father: | Charles II, Landgrave of Hesse-Philippsthal |
| Mother: | Marie of Württemberg |
| Birth Place: | Philippsthal |
| Death Place: | Eisenach |
Ernest Eugene Charles Augustus Bernard Paul of Hesse-Philippsthal (German: Ernst Eugen Karl August Bernhard Paul von Hessen-Philippsthal; born: 20 December 1846 in Philippsthal; died: 22 December 1925 in Eisenach) was a member of the House of Hesse and was the last ruling Landgrave of Hesse-Philippsthal.
Ernst was the eldest son of the Landgrave Charles II of Hesse-Philippsthal (1803-1868) from his marriage to Duchess Marie of Württemberg (1818-1888), a daughter of Duke Eugen of Württemberg.
After the Electorate of Hesse including Hesse-Philippsthal was annexed by Prussia in 1866, Ernest resigned on all subsequent claims on Hesse-Philippsthal in 1868, together with Landgrave Alexis of Hesse-Philippsthal-Barchfeld. In 1880, he received as compensation an annual income of, plus the Hanau City Castle in Hanau, Rotenburg Castle and Schönfeld Castle in Kassel.
Ernest died in 1925 unmarried and without descendants. With his death, the main Hesse-Philippsthal line of the House of Hesse died out; only the junior lines Hesse-Philippsthal-Barchfeld and Hesse-Kassel-Rumpenheim remained; the first inherited his estate.