Saint-Nicolas is a municipality of Belgium. It lies in the country's Walloon Region and Province of Liege. It is effectively a part of the greater Liège conurbation stretching west from Liège city centre towards Liège airport. As of January 1, 2006 Saint-Nicolas had a total population of 22,666. The total area is 6.84 km² which gives a population density of 3,313 inhabitants per km². It has the highest population density of any Belgian municipality outside the Brussels-Capital Region.
Since 1977 the municipality comprises the old municipalities of Montegnée, Saint-Nicolas and Tilleur.
Well known natives include the singer Sandra Kim who won the Eurovision Song Contest 1986 held in Bergen, Norway, 1986, the singer Mario Barravecchia and the soccer player Roberto Bisconti.