| Bernhard III | |
| Prince of Anhalt-Bernburg. | |
| Spouse: | Agnes of Saxe-Wittenberg Matilda, daughter of Albert I, Prince of Anhalt-Zerbst Matilda, daughter of Magnus I, Duke of Brunswick-Lüneburg |
| Consort: | no |
| House: | House of Ascania |
| House-Type: | Royal house |
| Father: | Bernhard II, Prince of Anhalt-Bernburg |
| Mother: | Helene of Rügen |
Bernhard III, Prince of Anhalt-Bernburg (died 20 August 1348) was a German prince of the House of Ascania and ruler of the principality of Anhalt-Bernburg.
He was the eldest son of Bernhard II, Prince of Anhalt-Bernburg, by his wife Helene, daughter of Wizlaw II, Prince of Rügen.
Bernhard succeeded his father as ruler of Anhalt-Bernburg after his death in 1323. His two younger brothers renounced their rights in order to become priests, which left Bernhard as sole ruler of Bernburg. Along with his princely title, he also used the styles "Count of Askanien" and "Lord of Bernburg".
In 1328 Bernhard married Agnes (c. 1310 – 4 January 1338), daughter of Rudolph I, Elector of Saxony and Duke of Saxe-Wittenberg. Her paternal grandmother and namesake Agnes of Habsburg was a daughter of Rudolph I, King of the Romans. The spouses were third cousins: Agnes's great-grandfather Albert I, Duke of Saxony, was a brother of Henry I, Count of Anhalt, Bernhard's great-grandfather.
Bernhard and Agnes had five children:
In 1339 Bernhard married for a second time to Matilda (died c. 1342), daughter of Albert I, Prince of Anhalt-Zerbst. Bernhard was more closely related to his bride, being a second cousin: Matilda's grandfather was Siegfried I, Prince of Anhalt-Zerbst, younger brother of Bernhard I, Prince of Anhalt-Bernburg, Bernhard's grandfather. The marriage was childless.
In c. 1343, Bernhard married for a third time to another Matilda (died after 28 June 1354), daughter of Magnus I, Duke of Brunswick-Göttingen. Through her mother Sophie of Brandenburg, Matilda was a great-great-great-granddaughter of Otto I, Margrave of Brandenburg, older brother of Bernhard, Count of Anhalt, Bernhard's great-great-grandfather.
Bernhard and Matilda of Brunswick-Göttingen had two children: