TheHeidi Horton Collection said in a statement that Horten died Sunday at the age of 81.
The museum said that Horten died early Sunday morning at her home at Lake Wrthersee.
Horten's private art collection has more than 16,000 square feet of exhibition space and is devoted to emerging and mid-career artists, many of whom are Austrian.
Horten became an overnight sensation when she spent up to $22 million on art in a single auction.
TheHeidi Horten Collection will be giving away free admission for the next week.
A total of $29 billion. Horten is the 1,040th wealthiest person in the world according to Forbes.
Horten met her future husband at a bar. Horten left a fortune of $1 billion. Horten started collecting art before her husband died, and eventually came to own hundreds of works. Horten sat on the board of a foundation that supports medical research and health care institutions, as well as serving as president of a hockey team.
Horten said that he was proud that his collection and the construction of the museum had created something lasting and that future generations would be able to experience it.