The National Gallery holds the principal collection of Slovenian art from the medieval period to the early twentieth century, in a building connected to a new wing added in 2001. The medieval sculpture section includes original Gothic stone carvings from Slovenian churches. The main collection covers Slovenian painting from the Baroque through the nineteenth century, including work by Rihard Jakopič and other post-Impressionist painters of the Slovenian Impressionist school.
The museum is also notable for holding the original Robba Fountain — the eighteenth-century baroque fountain of three figures that originally stood in front of the Town Hall was moved here for preservation; the one outside the Town Hall is a faithful copy.