In the 18th century, Didinium was discovered by the naturalist O.F. Müller and described in his Animalcula Infusoria under the name Vorticella nasuta. In 1859, Samuel Friedrich Stein moved the species to the newly created genus Didinium, which he placed within the order Peritricha, alongside other ciliates which have a ciliary fringe at the anterior of the cell, such as Vorticella and Cothurnia.
In the 18th century, O.F. Müller discovered and described the organism now known as Didinium under the name Vorticella nasuta. In 1859, Samuel Friedrich Stein moved this species to the genus Didinium, placing it within the order Peritricha alongside other ciliates with a ciliary fringe at their front end, such as Vorticella and Cothurnia.