Heinrich XVIII. Reuß zu Obergreiz, Herr zu Obergreiz, Herr zu Kranichfeld, Herr zu Lobenstein, Herr zu Schleiz, was born 28 February 1563 in Weida, Thuringia, Germany to Heinrich XV. Reuß zu Obergreiz (1525-1578) and Marie Salome von Öttingen (1535-1603) and died 16 January 1616 Schleiz, Thuringia, Germany of unspecified causes. He married Agnes Marie von Erbach-Erbach (1573-1634) 5 May 1593 in Obergreiz.
On his death, his lands went to other lines of the House of Reuß.