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.

From 1880, Alexis and Ernest of Hesse-Philippsthal together received, as heirs of the Landgraves of Philippsthal, a pension of 300000Mark from the Electorate of Hesse Trust Fund.

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.

He was succeeded as titular Landgrave of Hesse-Philippsthal-Barchfeld by his nephew Chlodwig (1876-1954), the son of his brother William (1831-1890).