Modelled after the famous Hlebine in Croatia, Trebnje Gallery is the only gallery in Slovenia which specialises in naïve art. It displays works from its permanent collection of Slovene naïve, organises annual international meetings and promotes Slovene naïve art abroad.

The first meeting of 'naïve' artists in Trebnje took place in 1967, and since that time the collection has grown to over 950 works. The Gallery represents 240 artists from 33 countries in Europe, Africa, Asia, the two Americas and Australia. Among the Slovene artists represented are Anton Repnik, Jože Peternelj-Mauser, Konrad Peternelj-Slovenec, Viktor Magyar, Greta Pečnik, Jože Horvat-Jaki, Irena Polanec and Boris Žohar. Significant Croatian naïve artists whose works are in the collection include Ivan Rabuzin and Ivan Lacković-Croata. Wooden sculptures have also been contributed by Janko Dolenc, Franc Tavčar and Croatian artist Petar Smajić. In 2004, at the World Exhibition of Naïve Art organised by UNESCO in Brno, the Gallery received a special mention from the jury.