Greiz (/ɡraɪts/ gryts) is a Kreis (district) in the east of Thuringia, Germany.

Historically the area of the district was part of the Vogtland, named after the title Vogt given to the local rulers in the 13th century.

Only two lines of the Reuß family survived from that time, with one principality based in Greiz, and the other in Gera and Schleiz.

A subcamp of the Buchenwald concentration camp was located at Berga/Elster during World War II.

It was an SS joint venture, in which inmates dug tunnels and laid railway tracks for the Schwalbe V project.