The town was first mentioned in 1043 as Scirnbeci. From 1180 on the Scharmbeck belonged to the Prince-Archbishopric of Bremen. The monastery in Osterholz was founded in 1182 and persisted until 1650, when Lower Saxony became mostly Protestant. In 1648 the Prince-Archbishopric was transformed into the Duchy of Bremen, which was first ruled in personal union by the Swedish and from 1715 on by the Hanoverian Crown. In 1823 the Duchy was abolished and its territory became part of the Stade Region in the Kingdom of Hanover.
In 1927 the two communities of Osterholz and Scharmbeck were merged under the name of Osterholz-Scharmbeck and in 1929 town privileges were granted.