Gustav III's Pavilion, Royal pavilion in Haga Park, Sweden

Gustav III's Pavilion is a royal pavilion in Haga Park, built 1787–1792 to designs by Olof Tempelman. Its long axis runs north–south: a three-storey central block with an attic, flanked by single-storey wings with five tall windows each, the roofline edged by a balustrade. The facade was originally yellow and undecorated; grey plaster ornament and Italian marble columns were added in the 1840s. Inside, Louis Masreliez decorated the Great Salon, the King's Dining Room and the Hall of Mirrors.

Gustav III bought the Brahelund estate in 1785 and had Olof Tempelman design the pavilion around the older "Stenhuset" core; the king approved the drawings on 29 May 1787. He moved in on 10 December 1790, and from here he left for the masquerade at the Opera on 16 March 1792 where he was assassinated. Duke Charles then used it as a temporary residence.

The King's Dining Room was painted as a Roman temple, with Corinthian marble pilasters and reliefs honouring Bacchus; Oscar I had it redone in Pompeian style in the 1840s before its 1930s reconstruction. The Mirror Salon, called the Lecturer's Room in Gustav III's day, was meant for readings from literary works.

The pavilion stands in Haga Park, about 2 km north of Stockholm, in Solna Municipality. The main entrance faces north, but Gustav III and his guests probably used another door. The Hall of Mirrors has high windows on three sides facing the park and Brunnsviken. The middle copper tent now holds the Haga Park Museum, the east tent a restaurant and the west tent accommodation.

The Sultan's Copper Tents beside the pavilion were designed by Louis Jean Desprez and built 1787–1790 as quarters for the palace guard. Only the facades facing the lawns were painted as Turkish tents in copper plate, creating the illusion of a sultan's encampment. The middle tent burned in 1953 and was rebuilt 1962–1964; it now houses the Haga Park Museum.