Ælfthryth, Countess of Flanders
| Ælfthryth of Wessex | |
|---|---|
| Countess consort of Flanders | |
| Tenure | 893/899 – 918 |
| Born | c. 877 |
| Died | 7 June 929 |
| Spouse | Baldwin II, Margrave of Flanders |
| Issue | Arnulf I of Flanders Adalulf, Count of Boulogne Ealswid Ermentrud |
| House | Wessex |
| Father | Alfred the Great |
| Mother | Ealhswith |
Ælfthryth of Wessex (c. 877 – 7 June 929), also known as Elftrudis (Elftrude, Elfrida), was an English princess and a countess consort of Flanders to Baldwin II.