Singaporean citizenship may be acquired through one of four ways- by birth, by descent, by registration, and by naturalisation. Citizenship is granted by birth to a child born in Singapore to legally married parents whereby at least one such parent is a Singaporean citizen, excluding certain circumstances.
A child born outside of Singapore to legally married parents whereby at least one such parent is a Singaporean citizen, also acquires Singaporean citizenship. Should the child also hold a foreign citizenship from the country of birth, this must be renounced by the age of 22, or their Singaporean Citizenship will be revoked.
Certain people may register for Singaporean citizenship provided they meet the criteria set down in Part X of the Constitution. Qualifying persons include individuals over 21 years of age residing in Singapore, women married to a Singaporean citizen, and children under 21 years of age residing in Singapore and being borne to a legally married Singapore citizen.
Additionally, a person over 21 years of age intending to reside in Singapore permanently may seek a certificate of naturalisation if he/she has resided in Singapore for not less than 10 years in the 12 years prior to the date of his application, subject to his/her being of good character and having an adequate knowledge of the national language.
Dual citizenship is not permitted in Singapore, therefore, a person who intends to become a Singaporean citizen must renounce his/her foreign citizenship. The government may deprive a national of his/her Singaporean citizenship should such person acquire or continue to retain a foreign citizenship after the age of 18.