The Palace of the Parliament (Romanian: Palatul Parlamentului), initially designed during Communist times as the People's House (Casa Poporului) or (less frequently used) the House of the Republic (Casa Republicii), is the seat of the Parliament of Romania, located atop Dealul Spirii in Bucharest, the national capital. The Palace reaches a height of 84 m (276 ft), is 92 m (302 ft) deep underground, has a floor area of 365,000 m² (3,930,000 sq ft) and a volume of 2,550,000 m³ (90,000,000 cu ft). The Palace of the Parliament is the heaviest building in the world, weighing about 4,098,500 tonnes (9.04 billion pounds), and is the largest civilian administrative building in the world, the largest military administrative building being the yet larger US Pentagon (cf. List of largest buildings). The Independent described it as the third best building in the world - "Hideous but also sort of impressive."

The building was designed and supervised by chief architect Anca Petrescu, with a team of approximately 700 architects, and constructed over a period of 13 years (1984–1997) in modernist Neoclassical architectural forms and styles, with socialist realism in mind. The Palace was ordered by Nicolae Ceaușescu (1918–1989), the president of Communist Romania.

Known for its ornate interior composed of 23 sections, the palace houses the two chambers of the Parliament of Romania: the Senate (Senat) and the Chamber of Deputies (Camera Deputaților), the Constitutional Court, along with three museums and an international conference centre. The museums in the Palace are the National Museum of Contemporary Art, and the Museum of the Palace. Though originally named the House of the Republic when under construction, the palace became widely known as the "People's House" after the Romanian Revolution of December 1989. Due to its impressive characteristics, events organized by state institutions and international bodies such as conferences and symposia take place there, but despite this about 70% of the building remains empty.

As of 2020^[update], the Palace of the Parliament is valued at €4 billion, making it the most expensive administrative building in the world. The cost of heating and electricity alone exceeds $6 million per year.

The old Palace of the Chamber of Deputies is now the Palace of the Patriarchate.

The Palace is in Sector 5 in the central part of Bucharest, at the top of Dealul Spirii (Spirea's Hill), also known as Dealul Arsenalului (Arsenal Hill). It is at the west end of the 3.5-kilometre (2.2 mi) Bulevardul Unirii (Union Boulevard), constructed at the same time as the Palace, and is ringed by Izvor Street to the west and northwest, United Nations Avenue to the north, Liberty Avenue to the east and Calea 13 Septembrie to the south.

The construction of the Palace of the Parliament was the most extreme expression of the systematization program imposed on Romania by Nicolae Ceaușescu. Systematization was a program of urban planning carried out by Ceaușescu, who was impressed by the societal organization and mass adulation he saw in North Korea's Juche ideology during his East Asia visit in 1971. Ceaușescu decided to implement similar policies in his country, with the stated goal of turning Romania into a "multilaterally developed socialist society."

A systematization project existed since the 1930s (during the time of King Carol II) for the Unirii–Dealul Arsenalului area. The Vrancea earthquake of 4 March 1977 gave Ceaușescu a pretext to demolish parts of old Bucharest. He wanted a civic center more in line with the country's political stance and started a reconstruction plan of Bucharest based on the socialist realism style. The House of the Republic was the centrepiece of Ceaușescu's project. Named Project Bucharest, it began in 1978 as an intended replica of the North Korean capital, Pyongyang. North Korean President Kim Il Sung had started construction on a similarly monumental residence, the Kumsusan Palace, two years earlier.