Gripsholm Castle, Renaissance castle and portrait gallery in Mariefred, Sweden.

Gripsholm Castle is a Renaissance castle on the shore of Lake Mälaren at Mariefred, built from brick around four round towers. Inside, halls hold the National Portrait Gallery's paintings of prominent Swedes, alongside furniture and applied art from the 1500s onward.

Gustav Vasa had Gripsholm Castle built in 1537 on the site of an older fortress, and by 1548 the castle held 98 paintings, 23 of them portraits. From Gustav III's accession in 1771 the collection began to include non-royal sitters. The National Portrait Gallery was officially founded in 1822, when Karl XIV Johan tasked Adolf Ludvig Stierneld with developing the Swedish gallery.

Since 1959 the Gripsholm Society has commissioned and donated a portrait of a notable Swede each year. The subjects include Olof Palme, Dag Hammarskjöld, Birgit Nilsson, Astrid Lindgren, Ingmar Bergman and Benny Andersson. The portraits are hung in the castle alongside the older collection.

Gripsholm Castle stands by Lake Mälaren at Mariefred, roughly 60 km west of Stockholm, reached by regional train to Läggesta and then bus or on foot. The portrait collection is shown in the castle's state rooms, so allow time to move between floors. Nationalmuseum has cared for the collection since 1860.

One of the round towers holds a Renaissance theater that King Gustav III installed in the 18th century. The original stage machinery still works and reveals how theater was produced centuries ago.