Spa is a municipality located in the Belgian province of Liège. On January 1st, 2002 Spa had a total population of 10,394 (4,965 males and 5,429 females). The total area is 39.82 km² which gives a population density of 261.02 inhabitants per km².

Spa is now also used as a generic term for a place where water believed to have special health giving properties occurs.

The largest thermal lake in the world, Lake Hévíz (Hévíz Spa) is located in Hungary.