The Sibbersdorfer See is a lake in the district of Ostholstein within the region known as Holstein Switzerland in the North German state of Schleswig-Holstein.

It has an area of 60 hectares (150 acres), is up to 7 metres deep, lies at an elevation of about 26.8 m above sea level (NN) and is crossed by the River Schwentine.

There is a gull island, about 5,000 square metres in area in the Sibbersdorfer See.

When this practice ended, the island became increasingly overgrown as it was no longer mown.

The Eutin-Malente Bird Conservation Group took over this maintenance function in 1995 and the number of breeding pairs increased again.