Astrid Njalsdotter or str r Nj lsd ttir was, according to Hervarar saga, the Norwegian-born mother of the Swedish king Stenkil. All our knowledge about her come from this source and it reads as follows:

There was a powerful high-born man in Sweden called Steinkel. His mother was Astrid, the daughter of Njal Finnson the Squinter from Halogaland, and his father was Rognvald the Old.

Her husband Ragnvald is usually identified with Ragnvald Ulfsson, the earl of Staraya Ladoga. This identification must however be regarded as guesswork since it is not supported by any other source. The Icelandic sagas mention a wife and two sons to Ragnvald Ulfsson but none are identical with Stenkil or his mother Astrid.