Éléonore Desmier d'Olbreuse
| Éléonore Desmier | |
|---|---|
Portrait, c. 1658. Attributed to German School, Brunswick. Royal Collection, Great Britain. | |
| Duchess consort of Brunswick-Lüneburg | |
| Tenure | 24 April 1676 – 28 August 1705 |
| Duchess consort of Saxe-Lauenburg | |
| Tenure | 30 September 1689 – 28 August 1705 |
| Born | January 1639 probably the Château d'Olbreuse, now in Deux-Sèvres, France |
| Died | 5 February 1722 (aged 83) Celle Castle, Celle, Germany |
| Burial | Stadtkirche, Celle, Germany |
| Spouse | |
| Issue | Sophia Dorothea, Electoral Princess of Hanover |
| House | Olbreuse (by birth) Welf (by marriage) |
| Father | Alexandre Desmier, seigneur d'Olbreuse |
| Mother | Jacquette Poussard du Bas-Vandré |
Éléonore Desmier d'Olbreuse (3, 7 or 9 January 1639 – 5 February 1722), was a French noblewoman, who became firstly the mistress and later wife of George William of Brunswick, Duke of Lauenburg and Prince of Celle. She was the mother of Sophia Dorothea of Celle, who was the wife of George I of Great Britain. Thus she was the maternal grandmother of George II.