The Palace of the Parliament (Romanian: Palatul Parlamentului) in Bucharest, Romania is a multi-purpose building containing both chambers of the Romanian Parliament. According to the Guinness Book of World Records, the Palace is the world's largest civilian administrative building, most expensive administrative building, and heaviest building.

The Palace was designed and nearly completed by the Ceauşescu regime as the seat of political and administrative power. Nicolae Ceauşescu named it the House of the Republic (Casa Republicii), but many Romanians call it the People's House (Casa Poporului). This probably is the most popular structure in Romania. Tours are available at the airport for the arrivals, including transport from the airplane right to the Palace.

The Palace measures 270 m (890 ft) by 240 m (790 ft), 86 m (282 ft) high, and 92 m (302 ft) underground. It has 1,100 rooms, 2 underground parking garages and is 12 stories tall, with four underground levels currently available for the general public and in use, and another four in different stages of completion.

The structure combines elements and motifs from multiple sources, in an eclectic neoclassical architectural style. The building is constructed almost entirely of materials of Romanian origin. Estimates of the materials used include one million cubic meters of marble from Transylvania, most from Ruşchiţa; 3,500 tonnes of crystal — 480 chandeliers, 1,409 ceiling lights and mirrors were manufactured; 700,000 tonnes of steel and bronze for monumental doors and windows, chandeliers and capitals; 900,000 m2 (9,700,000 sq ft) of wood, over 95% of which is domestic, for parquet and wainscoting, including walnut, oak, sweet cherry, elm, sycamore maple; 200,000 m2 (2,200,000 sq ft) of woolen carpets of various dimensions, the larger of which were woven on-site by machines moved into the building; velvet and brocade curtains adorned with embroideries and passementeries in silver and gold.

Built on the site of a hill variously known as Spirii Hill, Uranus Hill, or Arsenal Hill, which was largely razed for this megaproject, the building anchors the west end of Bulevardul Unirii and Centrul Civic. Constructing the Palace and Centrul Civic required demolishing much of Bucharest's historic district, including 19 Orthodox Christian churches, six Jewish synagogues, three Protestant churches (plus eight relocated churches), and 30,000 residences.

Construction began in 1983; the cornerstone was laid on 25 June 1984. While the building was intended to house all four major state institutions (in a similar manner to the UK Houses of Parliament), Ceausescu intended the palace to be his personal residence and the government was to operate in it (as if combining the Kremlin into one building). It was intended to house these institutions: The Presidency of the Republic (Preşedinţia Republicii) - today's Presidency (Preşedinţia); The Great National Assembly (Marea Adunare Naţionalǎ) - today's Parliament (Parlamentul); Consiliul de Miniştri - today's Government (Guvernul); Supreme Court (Tribunalul Suprem) - today's High Court of Cassation and Justice (Înalta Curte de Casaţie şi Justiţie). This explains the building's rectangular shape.

At the time of Nicolae Ceauşescu's 1989 overthrow and execution, the building structure and design were complete. Subsequently, many of the furnishings were never installed (mostly evident because of the many large, empty spaces throughout the palace), while the last three basement levels and a large clock tower (that would display the official Romanian time) were never finished. During the regime change, the new leaders of Romania referred to the building as the House of Ceauşescu, to highlight the excessive luxury in which Ceauşescu would have lived, in stark contrast to the squalor and poverty endured by many people living in the surrounding neighborhoods.

Parts of the building (some of the west wing, some of the east wing, parts of the second floor, basement 3 and everything below) are yet to be completed. Currently, a new underground car-park is being built inside a former stadium, currently used as a warehouse, which was covered during the construction of the palace. Tunnels linking 13 Septembrie Avenue with the basement of the building are planned to be built. It is said that Ceauşescu had built bunkers under the building where he would hide in case of a revolution.

Since 1997, the building has housed Romania's Chamber of Deputies, which had previously been housed in the Palace of the Patriarchy; the Romanian Senate joined them there in 2005, having previously been housed in the former Communist Party Central Committee building. The Palace also contains a massive array of miscellaneous conference halls, salons, etc. used for a wide variety of other purposes.

In 2003-2004 a glass annex was built , alongside external elevators. This was done to facilitate access to the National Museum of Contemporary Art (MNAC) opened in 2004 inside the west wing of the Palace of the Parliament, and to the Museum and Park of Totalitarianism and Socialist Realism, also opened in 2004.

The cafeteria for use of the legislators has been refurbished. Also in the building is the headquarters of the Southeast European Cooperative Initiative (SECI), an organization focused on regional cooperation among governments against cross-border crime. There are public tours organized in a number of languages. In 2008, the Palace hosted the 20th NATO summit. In 2002, Costa Gavras shot scenes of the film Amen in the Palace, meant to represent the Vatican. n 2009, the Palace appeared in Episode 1, Series 14 of the BBC motoring programme Top Gear, where the presenters, Jeremy Clarkson (in an Aston Martin DBS Volante), Richard Hammond (in a Ferrari California) and James May (in a Lamborghini LP560-4 Spyder) had a "Sat-Nav" race to the Palace, and are then shown driving throughout its underground tunnels and garages.