Countess Palatine Ernestine of Sulzbach (15 May 1697 – 14 April 1775) was the wife of Landgrave William "the Younger" of Hesse-Wanfried and after his death prioress of the Carmelite monastery in Neuburg an der Donau as Sister Teodora.

She was the third daughter of the Duke Theodore Eustace of Sulzbach and his wife Landgravine Maria Eleonore of Hesse-Rotenburg.

Ernestine and her older sister Countess Palatine Francisca Christina of Sulzbach were brought up in Essen Abbey.

After her husband died in 1731, she initially lived at Rheinfels Castle, later she moved into the Carmelites monastery in Neuburg an der Donau, where she was known under the religious name Sister Teodora and eventually became prioress.

According to Torsy and Kracht, she was a model for her sisters of obedience, humility and love of poverty.