Juliana of Hesse-Darmstadt (14 April 1606 in Darmstadt – 15 January 1659 in Osterode am Harz) was the wife of Count Ulrich II of East Frisia and was regent for her minor son Enno Louis from 1648 to 1651.

Juliana arrived in East Frisia on 5 March 1631 and married count Ulrich II on the same day.

Even during the turmoil of the Thirty Years' War Ulrich managed to build a Lustschloss for his wife at Sandhorst.

It was completed in 1648 even though East Frisia had to endure great hardship during the war, due to various foreign occupiers.

In the meantime, Juliana had moved the court from Aurich to Sandhorst to be able to indulge in the sweet life undisturbedly.