Until 1 January 2007 Ravnsborg was a municipality (Danish, kommune) on the northwest coast of the island of Lolland in the former Storstrøm County in south Denmark.
The municipality, including the islands of Fejø and Femø, covered an area of 198 km2, and had a total population of 5,569 (2005).
Its last mayor was Stig Vestergård, a member of the Social Democrats (Socialdemokraterne) political party.
Ferry service connects the former municipality to Langeland from a harbour west of the town of Sandby, and to the islands of Fejø and Femø from the town of Kragenæs.
This created a municipality with an area of 892 km2 and a total population of 49,469 (2005).