Daneliuska huset, Late 19th-century limestone building at Stureplan, Stockholm, Sweden.

Daneliuska huset is a limestone building in French Renaissance style located at the intersection of Birger Jarlsgatan and Biblioteksgatan. It features a distinctive conical tower and houses restaurants and shops on its ground levels.

Built 1898–1900 for salmon wholesaler Bror August Danelius to designs by Erik Josephson, who drew on Loire Valley castles such as Azay-le-Rideau and Chenonceau. In 1964 the Nessen firm sought demolition for a bank headquarters; a protest signed by about twenty cultural figures and Eva Remens's work in the city council led Stockholm to buy the house on 1 August 1968.

The building's nickname Strykjärnshuset (the Flatiron) comes from its wedge-shaped plot between three streets. The intertwined initials BAD of Bror August Danelius appear above the portal on Birger Jarlsgatan and on small coats of arms on the tower and Biblioteksgatan facade. Since the mid-1980s the name Arnoldshuset has survived in a conference centre in the building.

The building sits at the heart of Stureplan and is easily reached on foot from Stockholm's main streets. Visitors can view the exterior architecture or enter to access the shops and dining venues inside.

The intertwined initials BAD, for builder Bror August Danelius, appear above the Birger Jarlsgatan portal, on the Stureplan tower and on small coats of arms facing Biblioteksgatan. Danelius made his fortune partly in wholesale salmon.