Ilz is a municipality in the district of Hartberg-Fürstenfeld in Styria, Austria.

It was named first in a writ issued on 14 October 1265 in Graz by Herbord of Fullnstein, who was sewer of bishop Bruno of Olmütz.

In this writ a witness is mentioned: Dominus Wernherus de Ylnz, probably the vicar of that town.

In the 1980s the decay of the castle was imminent but the actual owners are restoring and adapting the building.

Ilz is situated near the Southern freeway (Exit 138) and at the Gleisdorfer highway (B65).