Gruber Palace, Late Baroque palace in Ljubljana, Slovenia.

Gruber Palace is a three-storey late Baroque and Rococo mansion at 1 Astronomy Street, east of Levstik Square. Its facade carries stucco ornament and a portrait of Gabriel Gruber by sculptor Janez Pirnat. Inside, an oval staircase with pastel stucco leads up beneath a domed ceiling painted in 1786 by Andrej Herrlein with an allegory of trade, crafts and technology.

Gabriel Gruber, a Jesuit hydraulics expert and architect from Vienna, began building the mansion in 1773 for a hydraulics and mechanics school; it was completed in 1777. After a fire on 28 June 1774 he bought the burnt plots and laid out a garden, and in 1784 he left Ljubljana and the palace was sold at auction. Owners included the amateur botanist Baron Nikodem Rastern and the deputy Anton Virant, who added a large house in 1842. The Carniolan Savings Bank bought it in 1887, and from 1965 it housed the Archives of the Republic of Slovenia.

The oval staircase's ceiling fresco, completed in 1786 by Andrej Herrlein, depicts trade, crafts and technology. The building's name comes from its founder Gabriel Gruber, and the street name Zvezdarska (Astronomy Street) recalls the observatory he planned here. A memorial plaque on the facade marks the 1896 founding of the Yugoslav Social Democratic Party in the building.

The building is home to the Archives of the Republic of Slovenia, which preserves national documents and historical records on site. The location is easy to find by the river, though the interior is typically closed to casual visitors since it functions as a working archive.

The chapel within the palace contains grisaille frescoes by J. M. Kremser-Schmidt, an 18th-century artist, depicting scenes from the life of the Virgin Mary. This rare monochrome painting technique showcases the artistic ambitions invested in decorating this building.