Unicameralism (from uni- "one" + Latin camera "chamber") is a type of legislature consisting of one house or assembly that legislates and votes as one. Unicameralism has become an increasingly common type of legislature, making up nearly 60% of all national legislatures and an even greater share of subnational legislatures.

Sometimes, as in New Zealand and Denmark, unicameralism comes about through the abolition of one of two bicameral chambers, or, as in Sweden, through the merger of the two chambers into a single one, while in others a second chamber has never existed from the beginning.

Rationale for unicameralism and criticism

The principal advantage of a unicameral system is more efficient lawmaking, as the legislative process is simpler and there is no possibility of deadlock between two chambers. Proponents of unicameralism have also argued that it reduces costs, even if the number of legislators stays the same, since there are fewer institutions to maintain and support financially. More popular among modern-day democratic countries, unicameral, proportional legislatures are widely seen as both more democratic and effective.

Proponents of bicameral legislatures say that having two legislative chambers offers an additional restraint on the majority, though critics note that there are other ways to restrain majorities, such as through non-partisan courts and a robust constitution.

List of unicameral legislatures

Countries with a bicameral legislatureCountries with a unicameral legislatureCountries with a unicameral legislature and an advisory bodyCountries with no legislature

Approximately half of the world's sovereign states are currently unicameral. The People's Republic of China is somewhat in-between, with a legislature and a formal advisory body. China has a Chinese People's Political Consultative Conference which meets alongside the National People's Congress, in many respects an advisory "upper house".

Many subnational entities have unicameral legislatures. These include the state of Nebraska and territories of Guam and the Virgin Islands in the United States, the Chinese special administrative regions of Hong Kong and Macao, the Australian state of Queensland as well as the Northern Territory and the Australian Capital Territory, a majority of the provinces of Argentina, all of the provinces and territories in Canada, all of the regions of Italy, all of the provinces of Nepal, all of the Spanish autonomous communities, both of the autonomous regions of Portugal, most of the states and union territories of India, all of the states of Nigeria, and all of the states of Brazil and Germany. In the United Kingdom, the devolved Scottish Parliament, the Welsh Senedd, the Northern Ireland Assembly, and the London Assembly are also unicameral.

National (UN member states and observers)

Federal

CountryUnicameral bodySeatsNotes
GermanyBundestag630The Bundestag is technically the unicameral parliament of Germany, since the Basic Law (German constitution) defines the Bundesrat not as a chamber of the legislature, but as a completely separate legislative institution.
IraqCouncil of Representatives329A provision exists for the founding of a "Council of Union", but no move to this effect has been initiated by the existing Council
MicronesiaCongress14
Saint Kitts and NevisNational Assembly15
United Arab EmiratesFederal National Council40
VenezuelaNational Assembly285

Unitary

CountryUnicameral bodySeatsNotes
AfghanistanLeadership Council30Purely advisory, powers reside in the emir.
AlbaniaKuvendi140
AndorraGeneral Council of Andorra28
AngolaNational Assembly220
ArmeniaNational Assembly107
AzerbaijanNational Assembly125
BangladeshJatiya Sangsad350
BeninNational Assembly109
BotswanaNational Assembly69
BruneiLegislative Council34Purely advisory, powers reside in the King
BulgariaNational Assembly240
Burkina FasoNational Assembly127
Cape VerdeNational Assembly72
Central African RepublicNational Assembly140
ChinaNational People's Congress2878
Costa RicaLegislative Assembly57
CroatiaSabor151
CubaNational Assembly of People's Power470
CyprusHouse of Representatives56
DenmarkFolketing179
DjiboutiNational Assembly65
DominicaHouse of Assembly32
East TimorNational Parliament65
EcuadorNational Assembly151
El SalvadorLegislative Assembly60
EritreaNational Assembly150
EstoniaRiigikogu101
FijiParliament55
FinlandParliament200
GambiaNational Assembly58
GeorgiaParliament150
GhanaParliament276
GreeceParliament300
GuatemalaCongress160
Guinea-BissauNational People's Assembly102
GuyanaNational Assembly65
HondurasNational Congress128
HungaryNational Assembly199
IcelandAlthing63
IranIslamic Consultative Assembly290
IsraelKnesset120
KazakhstanKurultai145transitional parliament from bicameralism to unicameralism with the new constitution approved in referendum on March 15, 2026. It will come into effect on July 1st of that same year
KiribatiHouse of Assembly45
North KoreaSupreme People's Assembly687
South KoreaNational Assembly300
KuwaitNational Assembly65
KyrgyzstanSupreme Council90
LaosNational Assembly164
LatviaSaeima100
LebanonParliament128
LibyaHouse of Representatives200
LiechtensteinLandtag25
LithuaniaSeimas141
LuxembourgChamber of Deputies60
MadagascarNational Assembly163Senate suspended
MalawiNational Assembly229
MaldivesMajlis93
MaliNational Assembly147
MaltaParliament79
Marshall IslandsLegislature33
MauritaniaParliament176
MauritiusNational Assembly66
MoldovaParliament101
MonacoNational Council24
MongoliaState Great Khural126
MontenegroParliament81
MozambiqueAssembly of the Republic250
NauruParliament19
New ZealandParliament123
NicaraguaNational Assembly90
NigerNational Assembly171
North MacedoniaAssembly120
NorwayStorting169
PalestineLegislative Council132
PanamaNational Assembly71
Papua New GuineaNational Parliament118
PortugalAssembly of the Republic230
QatarConsultative Assembly45
Saint Vincent and the GrenadinesHouse of Assembly21
SamoaLegislative Assembly51
Saudi ArabiaConsultative Assembly150Purely advisory, powers reside in the King
San MarinoGrand and General Council60
São Tomé and PríncipeNational Assembly55
SenegalNational Assembly165
SerbiaNational Assembly250
SeychellesNational Assembly34
Sierra LeoneParliament149
SingaporeParliament99
SlovakiaNational Council150
Solomon IslandsNational Parliament50
Sri LankaParliament225
SurinameNational Assembly51
SwedenRiksdag349
SyriaPeople's Assembly210
TanzaniaNational Assembly393
TongaLegislative Assembly26
TunisiaNational Assembly161
TurkeyGrand National Assembly600
TurkmenistanAssembly125
TuvaluParliament16
UgandaParliament529
UkraineVerkhovna Rada450
VanuatuParliament52
Vatican CityPontifical Commission8All powers delegated by the sovereign
VietnamNational Assembly500
ZambiaNational Assembly167

Territorial

CountryUnicameral bodySeatsNotes
Åland IslandsParliament30
AnguillaHouse of Assembly13
ArubaParliament21
AzoresLegislative Assembly57
BougainvilleHouse of Representatives41Autonomous region of Papua New Guinea
British Virgin IslandsHouse of Assembly15
Cayman IslandsLegislative Assembly21
Cherokee NationTribal Council17Indian reservation of the United States
Cook IslandsParliament24
CuraçaoParliament21
Falkland IslandsLegislative Assembly11
Faroe IslandsLøgting33
French PolynesiaAssembly57
GibraltarParliament17
GreenlandInatsisartut31Autonomous territory of the Kingdom of Denmark
GuamLehislaturan15Unincorporated territory of the United States
GuernseyStates40
Hong KongLegislative Council90
JerseyStates Assembly54
MadeiraLegislative Assembly47
MacaoLegislative Assembly33
MontserratLegislative Assembly11
Navajo NationTribal Council24Indian reservation of the United States
New CaledoniaCongress54
NiueAssembly20
Pitcairn IslandsIsland Council10
Saint BarthélemyTerritorial Council19
Saint HelenaLegislative Council15
Saint MartinCollectivity of Saint Martin23
Saint Pierre and MiquelonTerritorial Council19
Sint MaartenParliament15
TobagoHouse of Assembly15
TokelauGeneral Fono20
Turks and Caicos IslandsHouse of Assembly21
U.S. Virgin IslandsLegislature15
Wallis and FutunaTerritorial Assembly20

State parliaments with limited recognition

CountryUnicameral bodySeatsNotes
AbkhaziaPeople's Assembly35
KosovoAssembly120
Northern CyprusAssembly of the Republic50
Sahrawi Arab Democratic RepublicNational Council53
South OssetiaParliament34
TaiwanLegislative Yuan113The original constitution is partially superseded by the additional articles only on Taiwan which replaced the tricameral parliament into a unicameral one. A sunset clause in the additional articles will terminate them in the event of a hypothetical resumption of ROC rule in mainland China.
TransnistriaSupreme Council33

Subnational

Federations

Provincial legislatures in Argentina

Devolved governments

Others

  • Local People's Congresses of all levels of provinces, regions, and municipalities of the People's Republic of China
  • National Council of the Palestine Liberation Organization

List of historical unicameral legislatures

National

Subnational

Other

Unicameralism in the Philippines

Though the current Congress of the Philippines is bicameral, the country experienced unicameralism in 1898 and 1899 (during the First Philippine Republic), from 1935 to 1941 (the Commonwealth era) and from 1943 to 1944 (during the Japanese occupation). Under the 1973 Constitution, the legislative body was called Batasang Pambansa, which functioned also a unicameral legislature within a parliamentary system (1973–1981) and a semi-presidential system (1981–1986) form of government.

The ongoing process of amending or revising the current Constitution and form of government is popularly known as Charter Change. A shift to a unicameral parliament was included in the proposals of the constitutional commission created by President Gloria Macapagal Arroyo. Unlike in the United States, senators in the Senate of the Philippines are elected not per district and state but nationally; the Philippines is a unitary state. The Philippine government's decision-making process, relative to the United States, is more rigid, highly centralised, much slower and susceptible to political gridlock. As a result, the trend for unicameralism as well as other political system reforms are more contentious in the Philippines.

While Congress is bicameral, all local legislatures are unicameral: the Bangsamoro Parliament, the Sangguniang Panlalawigan (Provincial Boards), Sangguniang Panlungsod (City Councils), Sangguniang Bayan (Municipal Councils), Sangguniang Barangay (Barangay Councils), and the Sangguniang Kabataan (Youth Councils).

Unicameralism in the United States

Three U.S. states and territories have a unicameral legislature: the state of Nebraska, and the territories of Guam and the Virgin Islands.

The Nebraska Legislature (also called the Unicameral) is the supreme legislative body of the state of Nebraska and the only unicameral state legislature in the United States. Its members are called "senators", as it was originally the upper house of a bicameral legislature before the Nebraska House of Representatives dissolved in 1937. The legislature is also notable for being nonpartisan and officially recognizes no party affiliation, making Nebraska unique among US states. With 49 members, it is also the smallest legislature of any US state.

A 2018 study found that efforts to adopt unicameralism in Ohio and Missouri failed due to rural opposition. There was a fear in rural communities that unicameralism would diminish their influence in state government.

Local government legislatures of counties, cities, or other political subdivisions within states are usually unicameral and have limited lawmaking powers compared to their state and federal counterparts.

Some of the 13 colonies which became independent, such as Pennsylvania, New Jersey and New Hampshire had initially introduced strong unicameral legislature and (relatively) less powerful governors with no veto power. Pennsylvania's constitution lasted only 14 years. In 1790, conservatives gained power in the state legislature, called a new constitutional convention, and rewrote the constitution. The new constitution substantially reduced universal male suffrage, gave the governor veto power and patronage appointment authority, and added an upper house with substantial wealth qualifications to the unicameral legislature. Thomas Paine called it a constitution unworthy of America.[citation needed]

In 1944, Missouri held a vote on changing the General Assembly to a unicameral one, which was narrowly rejected by the voters 52.42–47.58. Only the city of St. Louis and the St. Louis County voted in favor, whilst Jackson County (containing the bulk of Kansas City) narrowly voted against, and all other counties voted against the change to unicameralism.

In 1970, North Dakota voters voted to call a constitutional convention. In 1972, a change to a unicameral legislature was approved by 69.36–30.64, however, since the voters rejected the new constitution at the same referendum, it never took effect.

In 1999, Governor Jesse Ventura proposed converting the Minnesota Legislature into a single chamber. Although debated, the idea was never adopted.

The US territory of Puerto Rico held a non-binding referendum in 2005. Voters approved changing its Legislative Assembly to a unicameral body by 456,267 votes in favor (83.7%) versus 88,720 against (16.3%). If both the territory's House of Representatives and Senate had approved by a 2⁄3 vote the specific amendments to the Puerto Rico Constitution that are required for the change to a unicameral legislature, another referendum would have been held in the territory to approve such amendments. If those constitutional changes had been approved, Puerto Rico could have switched to a unicameral legislature as early as 2015.

On June 9, 2009, the Maine House of Representatives voted to form a unicameral legislature, but the measure did not pass the Senate.

Because of legislative gridlock in 2009, former Congressman Rick Lazio, a prospective candidate for governor, has proposed that New York adopt unicameralism.

The United States as a whole was subject to a unicameral Congress during the years 1781–1788, when the Articles of Confederation were in effect. The Confederate States of America, pursuant to its Provisional Constitution, in effect from February 8, 1861, to February 22, 1862, was governed by a unicameral Congress.

See also

Further reading

  • Martin, Shane; Strøm, Kaare W. (2023). "Cameral Structures". Legislative Assemblies: Voters, Members, and Leaders. Oxford University Press. doi:. ISBN 9780198890829.

External links