Gripsholm Castle is a castle in Mariefred, Södermanland, Sweden. It is located by lake Mälaren in south central Sweden, in the municipality of Strängnäs, about 60 km west of Stockholm. Since Gustav Vasa, Gripsholm has belonged to the Swedish Royal Family and was used as one of their residences until the 18th century. It is now a museum, but is still considered to be a palace at the disposal of the King and as such it is part of the Crown palaces in Sweden.

Gustav I, commonly known as Gustav Vasa, was King of Sweden from 1523 until his death in 1560, previously self-recognised Protector of the Realm (Riksföreståndare) from 1521, during the ongoing Swedish War of Liberation against King Christian II of Denmark, Norway and Sweden. Gustav rose to lead the Swedish War of Liberation following the Stockholm Bloodbath, where his father was executed. Gustav's election as king on 6 June 1523 and his triumphant entry into Stockholm eleven days later marked Sweden's final secession from the Kalmar Union.