Singaporean nationality law
Singaporean nationality law is derived from the Constitution of Singapore and is based on jus sanguinis and a modified form of jus soli. There are four ways of acquiring Singaporean citizenship: by birth, by descent, by registration or by naturalisation. 
History of Singaporean citizenship
|British and Commonwealth
|Commonwealth nationality laws|
|Classes of citizens and subjects|
|Rights and visas|
Singaporean citizenship was first granted in 1959 when Singapore was a self-governing colony of the United Kingdom. At that time, Singapore had already been granted full internal self-government. Singapore Citizenship Ordinance 1957 provided Singaporean citizenship to all residents who were born in Singapore or the Federation of Malaya, British citizens who had been resident for two years, and others who had been resident for ten years. Singaporeans were still considered British subjects at that time, and their passports had the unusual nationality status of "British subject: citizen of the State of Singapore" instead of the usual "British subject: citizen of the United Kingdom and Colonies".
All Singaporean citizens became Malaysian citizens on 16 September 1963 upon Singapore's merger with Malaysia on that date. Malaysian nationality law provided that Singaporean citizenship to continue to exist as a subnational citizenship. Singaporean citizenship continued to be legislated by the Legislative Assembly of Singapore, subject to the approval of the Parliament of Malaysia. Singaporean citizenship was inseparable from Malaysian citizenship; in other words, it was not possible to have Singaporean citizenship without having Malaysian citizenship. The loss of one citizenship resulted in the loss of the other citizenship, except for provisions that allowed Singaporean citizens to register as Malaysian citizens without Singaporean citizenship.
Upon Singapore's secession from Malaysia on 9 August 1965, Malaysian citizenship was withdrawn from Singaporean citizens. Singaporean nationality law was incorporated into the new Constitution of Singapore. The constitution repealed the 1957 Ordinance, and all persons who were citizens as of 16 September 1963 by virtue of the Ordinance continued to be Singaporean citizens.
The Constitution was amended in 2004 to allow female citizens and citizens by descent to transmit their citizenship to children born overseas. For this to occur, citizens by descent must satisfy certain residency requirements.
Citizenship by birth
A person is a Singaporean citizen by birth if he or she is born in Singapore with at least one parent who is a Singaporean citizen provided both parents are registered officially as legally married.
However, a child whose father is a foreign diplomat who enjoys immunity in Singapore will not be granted Singaporean citizenship even if his or her mother is Singaporean. The gender-specific language of this clause allows an unusual scenario where a child born in Singapore whose mother is a foreign diplomat and whose father is Singaporean will obtain Singaporean citizenship by birth but not if the gender roles are reversed.
Citizenship by descent
A person born outside Singapore on or after 15 May 2004, with at least one parent who is a Singaporean citizen, is a Singaporean citizen by descent. If the parent from whom the child derives citizenship is a Singaporean citizen by descent, the parent must have been resident in Singapore for a total of at least four years before the child's birth or a total of at least one year out of the five years immediately preceding the child's birth.
A person born outside Singapore before 15 May 2004 will be a Singaporean citizen by descent only if his or her father was a Singaporean citizen by birth or by registration at the time of birth.
If the parent from whom the child derives citizenship is a Singaporean citizen by registration, the child will be granted Singaporean citizenship by descent only if they do not acquire citizenship of the country of their birth.
Citizenship by registration
Registration is the term used in the Constitution to refer to the process commonly known as naturalisation. A person can apply for registration as a Singaporean citizen if he or she has been a Permanent Resident for at least two years and is gainfully employed or married to a Singaporean citizen.  A male Permanent Resident may also apply upon satisfactory completion of full-time National Service, as may children of Singaporean citizens resident in Singapore. Each application is considered on its own merits.
Citizenship by naturalisation
Although provided for in the Constitution, citizenship by naturalisation is no longer granted. The government instead uses the constitutional provision for citizenship by registration to grant citizenship to resident aliens.
The position of the Singapore Government is that dual citizenship is not allowed. The laws regarding Singapore citizenship are found in the Constitution of Singapore.
A dual citizen may have acquired citizenship by birth in a foreign country, by descent from a foreign citizen parent, or by naturalisation. Singapore citizens who voluntarily and intentionally acquire citizenship of a foreign country after the age of 18 may be deprived of their Singapore citizenship by the Government. Foreigners who naturalise as Singaporean citizens are required to renounce all foreign citizenships. Persons who are born outside of Singapore and have at least one parent who is a Singapore citizen may register with a Singapore consulate within a year to acquire Singapore citizenship by descent. However, such persons must renounce their foreign citizenship, if any, before reaching 22 years of age. The Constitution of Singapore is silent on a Singapore citizen who acquired citizenship by birth and is a foreign citizen by descent. So long as such a person refrains from exercising the rights of foreign citizenship, the Government has no grounds for depriving him of his Singapore citizenship and he may hold on to dual citizenship.
The prohibition of dual citizenship is a contentious issue in Singapore. As the economy becomes more globalized and Singaporeans more mobile, many Singaporeans have acquired foreign citizenships and reluctantly renounced their Singaporean citizenship even though they may feel a strong emotional attachment to Singapore. Immigrants who have been resident in Singapore for long periods and qualify for Singaporean citizenship may be reluctant to become naturalized citizens as it would mean giving up the citizenship of their native countries.
The government argues that authorising its citizens to concurrently hold foreign nationalities would be undesirable since, due to Singapore's geopolitical position, it cannot afford to allow its citizens multiple allegiances which may be compromised in times of national crisis. The government also fears that those without a second citizenship may feel aggrieved if dual citizens enjoy the benefits of citizenship during periods of wealth but leave the country in trying times. Nevertheless, the government is open to the possibility of allowing dual citizenship if local and global circumstances demand so.
Renunciation of citizenship
Citizens of Singapore can only renounce Singaporean citizenship if they have acquired citizenship of another country. At the time of renunciation, renunciants must submit their Singaporean passports and National Registration Identity Cards for cancellation. About 1,200 Singaporean citizens renounce their citizenship every year, 300 of them are naturalised citizens. Male Singaporeans cannot renounce citizenship until completing national service. In 2012, a Hong Kong-born teenager filed a lawsuit regarding this requirement in order to give up his citizenship.
All Singaporean citizens are Commonwealth citizens and are entitled to certain rights in the United Kingdom and other Commonwealth countries. For example, they can vote in all elections (including for the European Parliament), hold public office and serve on juries in the UK. However, Singaporean citizens do not receive consular assistance from British embassies in non-Commonwealth countries without a Singapore representative unlike other Commonwealth nations, owing to the Singapore government's option not to afford Singaporeans this privilege.
These rights include:
- the right, unless otherwise disqualified (e.g. imprisoned), to vote in all elections (i.e., parliamentary, local and European  elections) as long as they have registered to vote (they must possess valid leave to enter/remain or not require such leave on the date of their electoral registration application)
- the right, unless otherwise disqualified, to stand for election to the British House of Commons as long as they possess indefinite leave to remain or do not require leave under the Immigration Act 1971 (c. 77) to enter or remain in the UK
- the right, if a qualifying peer or bishop, to sit in the House of Lords
- eligibility to hold public office (e.g., as a judge, magistrate, minister, police constable, member of the armed forces, etc.)
- Immigration and Checkpoints Authority
- Immigrant workers in Singapore
- National Registration Identity Card
- Nationality law
- Singapore passport
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- "History of Travel Documents & Passes". ICA. Retrieved 2014-03-07.
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- [dead link]
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- Article 134(1)(a) Constitution of the Republic of Singapore
- Article 126(1) Constitution of the Republic of Singapore
- Articles 122(4) and 126(3) for Singaporean citizens by descent and registration respectively, no provision for Singaporean citizens by birth
- Wong, Siew Ying (2005-05-27). "Singapore Won't Go the Path of Dual Citizenship: SM Goh". Channel NewsAsia.
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- [dead link]
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- "Judgments of the Court in Cases C-145/04 and C-300/04 – Kingdom of Spain v United Kingdom of Great Britain and Northern Ireland" (PDF). The Court of Justice of the European Communities. September 12, 2006. Retrieved 2007-12-18.
- Representation of the People Act 1983, Section 4(6)
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- Goh, Phai Cheng (1970). Citizenship Laws of Singapore. Singapore: Educational Publications Bureau.
- Tan, Kevin Y.L. (Yew Lee); Thio Li-ann (1997). Tan, Yeo & Lee's Constitutional Law in Malaysia and Singapore (2nd ed. ed.). Singapore: Butterworths Asia. ISBN 0-409-99908-3 (pbk.). , ch. 10 ("Citizenship")