Bertha of Blois, (fl. 1080), was a Duchess consort of Brittany and a countess consort of Maine, married in 1018 to Alain III, Duke of Brittany, and in 1046 to Hugh IV, Count of Maine. She was the daughter of Odo II, Count of Blois and Ermengarde of Auvergne.
| Preceded by Hawise of Normandy |
Duchess consort of Brittany 1018-1040 |
Succeeded by Constance of Normandy |
| Preceded by Rothild |
Countess consort of Maine 1046-1051 |
Succeeded by Eria of Hauteville |