Horne (also Horn, Hoorn or Hoorne) is a small historic county of the Holy Roman Empire in the present-day Netherlands and Belgium. It takes its name from the village Horn, west of Roermond. The residence of the counts of Horne was moved from Horn to Weert in the 15th century.

After the execution in 1568 of Philip de Montmorency who died without male heirs, the Prince-Bishop of Liège, as suzerain of Horne, was declared the direct lord and new count. The bishops ruled the county in personal union. Horne maintained its own laws and customs as well as its financial autonomy. The county included the communes of Neer, Nunhem, Haelen, Buggenum, Roggel, Heythuysen, Horne, Beegden, Geystingen and Ophoven.

It was suppressed in 1795, when it was occupied by the French, and it became part of the French département Meuse-Inférieure.