The Duchy of Styria was a duchy located in modern-day southern Austria and northern Slovenia. It was a part of the Holy Roman Empire until its dissolution in 1806 and a Cisleithanian crown land of Austria-Hungary until its dissolution in 1918.

A duchy, also called a dukedom, is a medieval country, territory, fief, or domain ruled by a duke or duchess, a ruler hierarchically second to the king or queen in Western European tradition.