Jalhay is a municipality of Belgium. It lies in the country's Walloon Region and Province of Liege. On January 1, 2006, Jalhay had a total population of 7,953. The total area is 107.75 km² which gives a population density of 74 inhabitants per km².
The municipality consists of the following sub-municipalities: Jalhay proper and Sart (or Sart-lez-Spa).
The highest point of the municipality is the Baraque Michel in the High Fens, at .