Balthasar von Dernbach (1548 – 16 March 1606), was a Benedictine monk of Fulda monastery and its Prince-Abbot from 1570 to 1606.
Balthasar was born into a branch (called Graul) of the von Dernbach family, a family of knights traceable to the 13th century in the vicinity of Giessen and Herborn as liegemen of the landgraves of Hesse.
Born in 1548 in Wiesenfeld, Hesse, Balthasar was the youngest son of the fifteen children of Peter von Dernbach and his wife, Clara Klauer von und zu Wohra. Balthasar was baptized into the Lutheran church, although his father's religious leanings have been described as either "staunchly Lutheran" and the "only Catholic" in Hesse. A liegeman of Philip I, Landgrave of Hesse, Peter von Dernbach fought in the Schmalkaldic War of 1546/47 despite adopting a critical attitude towards Philip's religious policies.
When Balthasar's father died in 1560, his mother sent the 12-year-old youth to Fulda monastery, where her brother, Wilhelm Hartmann Klauer von und zu Wohra, was prince-abbot. There Balthasar was raised a Catholic and in 1566 he was ordained a priest in Würzburg. In 1570, he was elected his uncle's successor as prince-abbot and confirmed in that position by Pope Pius V. As abbot, Balthasar helped his brothers Otto, Melchior and Wilhelm to high offices: Otto became marshall and provost at Petersberg, Melchior an court marshall, bailiff at Brückenau and imperial counsellor, and William commander of the joined the Teutonic Knights at Kapfenburg und Oettingen. Melchior's son Peter Philip entered the service of the Prince-Bishopric of Bamberg and later became Prince-Bishop of Bamberg and of Würzburg.
Balthasar immediately adopted a policy of counterreformation. In 1571 he called in the Jesuits to found a school and college. He insisted that the members of the chapter should return to a monastic form of life. Whereas his predecessors had tolerated Protestantism, resulting in most of the citizenry of Fulda and a large portion of the principality's countryside professing Lutheranism, Balthasar ordered his subjects either to return to the Catholic faith or leave his territories.