The Liège Revolution, sometimes known as the Happy Revolution, against the reigning prince-bishop of Liège, started on 18 August 1789 and lasted until the destruction of the Republic of Liège and re-establishment of the Prince-Bishopric of Liège by Austrian forces in 1791. The Liège Revolution was concurrent with the French Revolution and its effects were long-lasting and eventually led to the abolition of the Prince-Bishopric of Liège and its final annexation by French revolutionary forces in 1795.

The Prince-Bishopric of Liège or Principality of Liège was an ecclesiastical principality of the Holy Roman Empire that was situated for the most part in present-day Belgium. It was an Imperial Estate, so the bishop of Liège, as its prince, had a seat and a vote in the Imperial Diet. The Prince-Bishopric of Liège should not be confused with the Diocese of Liège, which was larger and over which the prince-bishop exercised only the usual responsibilities of a bishop.