Gisselfeld, a former monastery, is Denmark's fifth-largest estate. Located between Haslev and Næstved, it extends into several municipalities but the main building is located in Braaby Parish in Faxe Municipality. The estate measures 3,850 hectares, including Hesede, Edelesminde, Brødebæk and Gødstrupgård, of which 2,400 hectares is forest. The three-storeyed Renaissance-style building has stepped gables, loopholes and a projecting tower over the main gate. The grounds include a moat, a well-kept park, lake, waterfall, gardens, greenhouse, and a fountain. A recent addition in its forest is a 45-meter-tall (148 ft) hyperboloid tower.

Gisselfeld is first mentioned at the end of the 14th century when the owner was Bo Falk. At that time, there was a small manor situated some 2 km northwest of the site of today's main building. It stood next to an older fort, possibly the now demolished Valgestrup.

Gisselfeld was later owned by Bo Falk's son Peder Falk and grandson Eskild Falk. The latter's daughter Ida was married to Mogens Axelsen Gøye. Their son, Eskil Gøye, owned Gisselfeld from 1450. His other holdings included Krenkerup on Lolland and Turnbyholm in Skåne as well as the fiefs of Aalholm and Lindholm. He served as rigsmarsk from 1489.

Gisselfeld was upon Eskil Gøye's death in 1506 passed to his son Henrik Gøye. Krenkerup went to Henrik Jøye's elder brother Mogens Gøye. Henrik Gøye served as governor during the siege of Copenhagen. In c. 1523, he had to mortgage Gisselfeld to his cousin Otte Holgersen Rosenkrantz and brother Mogens Gøye.

Today's estate was founded by Peder Oxe til Nielstrup who built the manor from 1547 to 1575. It originally consisted of four interconnected red-brick wings, three storeys high with thick outer walls, a number of loopholes and large stepped gables. A protruding gate tower stands at the centre of the left wing. The fourth wing, now demolished, housed a chapel.

After Peder Oxe's death, his widow Mette Rosenkrantz til Vallø became the owner of the estate. After her death in 1588, her niece Karen Banner inherited Gisselfeld. She married Henrik Lykke til Overgaard whose family ran the estate until Kai Lykke was executed and relieved of all his rights in 1661.

After a short period of ownership by the Crown, in 1670 the property was presented to Count Hans Schack as a reward for the part he played in the Swedish wars. In 1688, his son Otto Diderik sold the estate to Adam Levin Knuth whose family maintained ownership until 1699.

In 1699, Christian V's illegitimate son took it over. As a result of his will, on his death in 1703 the manor should have become a convent but this did not happen until the death of his widow Dorothea Krag in 1754 extinguished her dower rights. Since 1755, under the name of Danneskiold-Samsøe his descendants have run the estate as "Gisselfeld Adelige Jomfrukloster I Sjælland" (Gisselfeld Convent in Zealand for Virgins of Noble Birth). The 11th in line, Helene Danneskiold-Samsøe, has run Gisselfeld since 2010.