By 1710 all her siblings had died and so, after her father's death Dorothea Wilhelmine was the last surviving member of the house of Saxe-Zeitz.

She married on 27 September 1717 in Zeitz with future Landgrave William VIII of Hesse-Kassel (1682–1760).

Queen Caroline of Great Britain reported to the Duchess of Orleans, the Landgravine "was ugly and had a weird head".

The new first lady at court was the Landgrave's favorite Barbara Christine von Bernhold whom he made Countess Bernold of Eschau while Dorothea Wilhelmine was still alive.

From their marriage, Dorothea Wilhelmine had the following children: This article about a German duchess is a stub.