The commonest ways in which a person can become a citizen of Nigeria as stipulated in the 1979 and 1999 constitutions of the Federal Republic of Nigeria are as follows:
(a) Citizenship of Birth
According to the constitution, the following persons are citizens of Nigeria:
(i) every person born in Nigeria before the date of independence, either of whose parents or any of whose grand parents belongs or belonged to a community indigenous to Nigeria,
(ii) every person born in Nigeria after the date of independence either of whose parents or any of whose grand parents is a citizen of Nigeria, (iii) every person born outside Nigeria either of whose parents is a citizen of Nigeria.
(b) Citizenship by Registration
The constitution provides that any woman who is or had been married to a citizen of Nigeria of any person of full age and capacity born outside Nigeria any of whose grandparents is a citizen of Nigeria, if the President is satisfied that:
(i) he is a person of good character.
(ii) he has shown a clear intention of his desire to be domiciled in Nigeria.
(iii) he has taken an oath of allegiance as prescribed in the constitution.
Most countries grant citizenship by registration to wives or husbands who were originally citizens of other countries.
(c) Citizenship by Naturalisation
This is the process by which an individual may voluntarily change his citizenship of a state to another state. The conditions under which naturalisation are conferred vary from country to country.
In Nigeria, no person shall be granted certificate of naturalisation, unless he satisfies the President that:
(i) he is a person of full age and capacity.
(ii) he is a person of good character.
(iii) he has shown a clear intention of his desire to be domiciled in Nigeria.
(iv) he is, in the opinion of the Governor of the state where he is or proposes to be resident, acceptable to the local community in which he is to live permanently and has been assimilated into the ways of life of Nigeria in that part of the federation.
(v) he is a person who has made or is capable of making useful contribution to the advancement, progress and well-being of Nigerians.
(vi) he has taken the oath of allegiance as prescribed in the constitution.
It is pertinent to note that only citizenship by birth gives the individual full right of citizenship without any strings attached to it. The granting of citizenship through registration or naturalisation is very conditional. Under these processes, citizenship can easily be withdrawn if the person breaks the condition.