| Cymburgis of Masovia | |
|---|---|
| Duchess of Austria | |
 Posthumous portrait by Anton Boys, c. 1580 | |
| Reign | 1412–1424 |
| Born | 1394 or 1397 Warsaw, Masovia |
| Died | 28 September 1429 Türnitz, Austria |
| Burial | |
| Spouse | Ernest, Duke of Austria |
| Issue | Frederick III, Holy Roman Emperor Margaret Albert VI, Archduke of Austria Alexander of Austria Rudolf of Austria Catherine of Austria Leopold of Austria Anna of Austria Ernest of Austria |
| House | Piast dynasty |
| Father | Siemowit IV, Duke of Masovia |
| Mother | Alexandra of Lithuania |
Cymburgis of Masovia (Polish: Cymbarka mazowiecka; German: Cimburgis von Masowien; 1394 or 1397 – 28 September 1429), also spelled Zimburgis or Cimburga, was a Princess of Masovia of the Polish Piast dynasty and a Duchess of Austria from 1412 until 1424, by her marriage with the Habsburg duke Ernest the Iron. As the mother of later Emperor Frederick III, Cymburgis, after Gertrude of Hohenberg, became the second female ancestor of all later Habsburgs, as only her husband's Ernestine branch of the family survived in the male line.