Apfelberg is a former municipality in the district of Murtal, in the Austrian state of Styria. It lies in the Murtal region of central Styria, the valley of the Mur river.
Since the 2015 Styria municipal structural reform, Apfelberg is no longer an independent municipality; it is now part of the municipality of Knittelfeld. The reform merged a number of small Styrian municipalities into larger administrative units, and Apfelberg was among those absorbed.
Its administrative association with Knittelfeld, a town in the same district, is the main fact defining Apfelberg today. Detailed information on its history, population, and landmarks is limited.