| Otto VI, Count of Tecklenburg | |
| Noble Family: | House of Hagen |
| Father: | Nicholas I, Count of Tecklenburg |
| Mother: | Helena of Oldenburg-Wildeshausen-Altbruchhausen |
| Spouse: | Adelaide of Lippe |
| Death Date: | 1388 |
Otto VI, Count of Tecklenburg (died 1388) was the only son of Count Nicholas I and his wife, Helena of Oldenburg-Wildeshausen-Alt-Bruchhausen. In 1367, he succeeded his father as count of Tecklenburg-Ibbenbüren and count of Lingen and Cloppenburg. In 1376, he became pledge holder of Iburg.
Otto was a bold fighter. He improved the administration of the county and granted city rights to Bevergen. He acquired the bailiwicks of Clarholz, Marienfeld and Herzebrock. His marriage with Adelaide of Lippe gave him a claim on the cities of Rheda and Lipperode. This led to a lengthy dispute, which was resolved in 1401 by a compromise between his son Nicholas II and his second cousin Simon III of Lippe: Nicholas received Rheda, and Lipperode became a condominium between Lippe and the County of Mark
From 1372 to 1379, Otto was also administrator of the Bishopric of Osnabrück, after he had deposed bishopMelchior. In 1379, he was besieged in Rheda and had to surrender.
Otto VI married Adelaide, the daughter of Lord Bernard V of Lippe. He had two children: