| Nicholas III, Lord of Mecklenburg | |
| Noble Family: | House of Mecklenburg |
| Father: | John I, Lord of Mecklenburg |
| Mother: | Luitgard of Henneberg |
| Birth Date: | after 1230 |
| Death Date: | 8 June 1289 or 1290 |
| Burial Place: | Doberan Minster |
Nicholas III, Lord of Mecklenburg (after 1230 - 8 June 1289 or 1290) was from 1264 to 1289 Lord of Mecklenburg.
He was the son of John I and his wife, Luitgard of Henneberg (1210-1267), the daughter of Count Poppo VII of Henneberg. On 9 January 1266, he was appointed canon of Lübeck Cathedral. In 1269 he was also a priest in the St. Mary's Church in Wismar.
When Henry I was taken prisoner during a pilgrimage to the Holy Land, Nicholas III and his brother John II took up the regency for Henry's underage sons. He is last mentioned as living in a document dated 2 April 1289.
He died on 8 June 1289 or 1290 and was buried in Doberan Minster.