| Alexis | |
| Landgrave of Hesse-Philippsthal-Barchfeld | |
| House: | Hesse |
| Father: | Charles, Landgrave of Hesse-Philippsthal-Barchfeld |
| Mother: | Princess Sophie of Bentheim and Steinfurt |
| Spouse: | Princess Louise of Prussia |
| Birth Place: | Burgsteinfurt |
| Death Place: | Herleshausen |
Alexis William Ernest Philip of Hesse-Philippsthal-Barchfeld (German: Alexis Wilhelm Ernst von Hessen-Philippsthal-Barchfeld; 13 September 1829 in Burgsteinfurt - 16 August 1905 in Herleshausen) was the last ruling Landgrave of Hesse-Philippsthal-Barchfeld.
Alexis was a son of the Landgrave Charles of Hesse-Philippsthal-Barchfeld (1784-1854) from his second marriage to Sophie (1794-1873), the daughter of Louis William Geldricus Ernest, Prince of Bentheim and Steinfurt. He succeeded his father in 1854 as Landgrave of Hesse-Philippsthal-Barchfeld.
Alexis was a Prussian General of the Cavalry à la suite. From 1866, he was a member of the Prussian House of Lords and a Knight of the Prussian Order of the Black Eagle.
Prussia annexed the Electorate of Hesse, including Hesse-Philippsthal-Barchfeld, in 1866. From 1880, Alexis and Ernest of Hesse-Philippsthal together received, as heirs of the Landgraves of Philippsthal, a pension of from the Electorate of Hesse Trust Fund. They were also given three castles: the City Castle in Hanau, Rotenburg Castle and Schönfeld Castle in Kassel.
On 17 June 1854, Alexis married at Charlottenburg Palace to Princess Louise of Prussia (1829-1901), the elder daughter of Prince Charles of Prussia and his wife, Princess Marie of Saxe-Weimar-Eisenach. The marriage remained childless and ended with a divorce on 6 March 1861.
Wilhelm died on 16 August 1905 in Herleshausen, Hesse, Germany. He was succeeded as titular Landgrave of Hesse-Philippsthal-Barchfeld by his nephew Chlodwig (1876-1954), the son of his brother William (1831-1890).