Agnes of Brunswick-Grubenhagen (born: c. 1406; died: 18 November 1439) was, from 1412 to 1439, abbess of Gandersheim Abbey as Agnes II.

She was about six years old when she was elected abbess of Gandersheim Abbey.

The pope confirmed Agnes's election while she was a minor, however, he appointed a dean of the Abbey as her guardian and regent.

In connection with the Guelph inheritance division[1] after the Lords of Homburg died out, she transferred the castle and town of Gandersheim and the castles of Seesen and Stauffenburg to Otto II of Brunswick-Göttingen.

This article about a member of the German nobility is a stub.