Lambert I von Tonna

Lambert I (c.1100–13 October 1149) was a younger son of Count Erwin I of Gleichen. He is documented from 1125 and appears as count of Tonna in 1134, and he married Mechtild, daughter of Count Theodoric of Are.

Lambert died at Erfurt on 13 October 1149 and was buried in Volkenroda Abbey, the house his mother had founded. A son, Lambert called the Younger, appears in charters in 1150 and 1151.