Tuvalu is a parliamentary democracy and Commonwealth realm with Queen Elizabeth II serving as the country's head of state and bearing the title Queen of Tuvalu. Since the Queen does not reside in the islands, she is represented in Tuvalu by a Governor General appointed by the Queen upon the advice of the Prime Minister of Tuvalu.

From 1974 (the creation of the British colony of Tuvalu) until independence, the legislative body of Tuvalu was called the House of the Assembly or Fale I Fono. Following independence in October 1978 the House of the Assembly was renamed the Parliament of Tuvalu or Palamene o Tuvalu.

The unicameral Parliament has 15 members with elections held every four years. The members of parliament select the Prime Minister (who is the head of government) and the Speaker of Parliament. The ministers that form the Cabinet are appointed by the Governor General on the advice of the Prime Minister.

There are no formal political parties and election campaigns are largely based on personal/family ties and reputations.

The Tuvalu National Library and Archives holds "vital documentation on the cultural, social and political heritage of Tuvalu", including surviving records from the colonial administration, as well as Tuvalu government archives.

There are eight Island Courts and Lands Courts; appeals in relation to land disputes are made to the Lands Courts Appeal Panel. Appeals from the Island Courts and the Lands Courts Appeal Panel are made to the Magistrates Court, which has jurisdiction to hear civil cases involving up to $T10,000.

 The superior court is the High Court of Tuvalu as it has unlimited original jurisdiction to determine the Law of Tuvalu and to hear appeals from the lower courts. Sir Gordon Ward is the current Chief Justice of Tuvalu.[79] Rulings of the High Court can be appealed to the Court of Appeal of Tuvalu. From the Court of Appeal there is a right of appeal to Her Majesty in Council, i.e., the Privy Council in London.

The Law of Tuvalu comprises the Acts voted into law by the Parliament of Tuvalu and statutory instruments that become law; certain Acts passed by the Parliament of the United Kingdom (during the time Tuvalu was either a British protectorate or British colony); the common law; and customary law (particularly in relation to the ownership of land).

Tuvalu participates in the work of Secretariat of the Pacific Community, or SPC (sometimes Pacific Community) and is a member of the Pacific Islands Forum, the Commonwealth of Nations and the United Nations. Tuvalu has maintained a mission at the United Nations in New York City since 2000. Tuvalu is a member of the World Bank and the Asian Development Bank.

Tuvalu maintains close relations with Fiji, New Zealand, Australia, Japan, South Korea, the United Kingdom and the European Union. It has diplomatic relations with the Republic of China (Taiwan); the ROC maintains the only resident embassy in Tuvalu and has a large assistance programme in the islands.

A major international priority for Tuvalu in the UN, at the 2002 Earth Summit in Johannesburg, South Africa and in other international fora, is promoting concern about global warming and the possible sea level rising. 

Tuvalu advocates ratification and implementation of the Kyoto Protocol. In December 2009 the islands stalled talks on climate change at the United Nations Climate Change Conference in Copenhagen, fearing some other developing countries were not committing fully to binding deals on a reduction in carbon emissions. Their chief negotiator stated, "Tuvalu is one of the most vulnerable countries in the world to climate change and our future rests on the outcome of this meeting."

Tuvalu participates in the Alliance of Small Island States (AOSIS), which is a coalition of small island and low-lying coastal countries that have concerns about their vulnerability to the adverse effects of global climate change.

Under the Majuro Declaration, which was signed on 5 September 2013, Tuvalu has commitment to implement power generation of 100% renewable energy (between 2013 and 2020), which is proposed to be implemented using Solar PV (95% of demand) and biodiesel (5% of demand).

The feasibility of wind power generation will be considered.[84] Tuvalu participates in the operations of the Pacific Islands Applied Geoscience Commission (SOPAC) and the Secretariat of the Pacific Regional Environment Programme (SPREP).

Tuvalu is party to a treaty of friendship with the United States, signed soon after independence and ratified by the US Senate in 1983, under which the United States renounced prior territorial claims to four Tuvaluan islands (Funafuti, Nukufetau, Nukulaelae and Niulakita) under the Guano Islands Act of 1856.

Tuvalu participates in the operations of the Pacific Island Forum Fisheries Agency (FFA) and the Western and Central Pacific Fisheries Commission (WCPFC). The Tuvaluan government, the US government, and the governments of other Pacific islands, are parties to the South Pacific Tuna Treaty (SPTT), which entered into force in 1988.[89] Tuvalu is also a member of the Nauru Agreement which addresses the management of tuna purse seine fishing in the tropical western Pacific. 

In May 2013 representatives from the United States and the Pacific Islands countries agreed to sign interim arrangement documents to extend the Multilateral Fisheries Treaty (which encompasses the South Pacific Tuna Treaty) to confirm access to the fisheries in the Western and Central Pacific for US tuna boats for 18 months.

 Tuvalu and the other members of the Pacific Island Forum Fisheries Agency (FFA) and the United States have settled a tuna fishing deal for 2015. The treaty is an extension of the Nauru Agreement and provides for US flagged purse seine vessels to fish 8,300 days in the region in return for a payment of US$90 million made up by tuna fishing industry and US-Government contributions.

In July 2013 Tuvalu signed the Memorandum of Understanding (MOU) to establish the Pacific Regional Trade and Development Facility, which Facility originated in 2006, in the context of negotiations for an Economic Partnership Agreement (EPA) between Pacific ACP States and the European Union. 

The rationale for the creation of the Facility being to improve the delivery of aid to Pacific island countries in support of the Aid-for-Trade (AfT) requirements. The Pacific ACP States are the countries in the Pacific that are signatories to the Cotonou Agreement with the European Union.