Rettenegg is a municipality in the district of Weiz, in the Austrian state of Styria. It is located in the eastern part of Styria, within the Weiz district, which lies in the broader Alpine region of southeastern Austria.
As a municipality, Rettenegg forms one of the local administrative units of the Weiz district. The district itself is part of the Austrian federal state of Styria, one of the country's nine states.