Belœil is a Belgian municipality located in the province of Hainaut. It is around 10 km south of Ath. On 1 January 2006 the municipality had 13,347 inhabitants. The total area is 61.55 km², giving a population density of 217 inhabitants per km².
The municipality is named after the château of Belœil, once the seat of Charles-Joseph, Prince of Ligne, a military officer and man of letters who corresponded with Jean-Jacques Rousseau and Voltaire.