Until January 1, 2007 Sydlangeland municipality was a municipality (Danish, kommune) in the former Funen County on the island of Langeland in south-central Denmark. The municipality covered an area of 121 km², and had a total population of 4,288 (2005). Its last mayor was Knud Gerther. The main town and the site of its municipal council was the town of Humble.
Ferry service connects the former municipality on the south end of the island at the town of Bagenkop over the Baltic Sea to the city of Kiel, Germany.
The municipality was created in 1970 due to a kommunalreform ("Municipality Reform") that combined a number of existing parishes:
Sydlangeland municipality ceased to exist as the result of Kommunalreformen ("The Municipality Reform" of 2007). It was merged with existing Tranekær and Rudkøbing municipality to form the new Langeland municipality. This created a municipality with an area of 290 km² and a total population of 14,223 (2005). The new municipality belongs to Region of Southern Denmark ("South Denmark Region").
Coordinates: 54°49′51″N 10°42′00″E / 54.83083°N 10.70000°E