Sir Robert Hales (c. 1325 – 14 June 1381) was Grand Prior of the Knights Hospitaller of England, Lord High Treasurer, and Admiral of the West.

In 1372 Robert Hales became the Lord/Grand Prior of the Knights Hospitallers of England.

Richard II appointed him Lord High Treasurer,[1] so he was responsible for collecting the hated poll tax.

[3] Robert Hales was present at many latter-day crusader expeditions, and is recorded as leading a contingent of hospitaller knights at the sacking of Alexandria.

Hales was described by the chronicler Thomas Walsingham as a "Magnanimous knight, though the Commons loved him not".