Official source page 26

ery person born outside Nigeria either of whose parents is a citizen of Nigeria. this section, "the date of independence" means the 1st day of October 1960. Subject to the provisions of section 28 of this Constitution, a person to whom the provisions of this section apply may be registered as a citizen of Niger President is satisfied that - is a person of good character; has shown a clear intention of his desire to be domiciled in Nigeria; and has taken the Oath of Allegiance prescribed in the Seventh Schedule to this Constitution. e provisions of this section shall apply to- y woman who is or has been married to a citizen of Nigeria; or ery person of full age and capacity born outside Nigeria any of whose grandparents is a citizen of Nigeria. Subject to the provisions of section 28 of this Constitution, any person who is qualified in accordance with the provisions of this section may apply to th dent for the same of a certificate of naturalisation. o person shall be qualified to apply for the grant of a certificate or naturalisation, unless he satisfies the President that - is a person of full age and capacity; is a person of good character; has shown a clear intention of his desire to be domiciled in Nigeria; is, in the opinion of the Governor of the State where he is or he proposes to be resident, acceptable to the local community in which he is to live anently, and has been assimilated into the way of life of Nigerians in that part of the Federation; is a person who has made or is capable of making useful contribution to the advancement; progress and well-being of Nigeria; has taken the Oath of Allegiance prescribed in the Seventh Schedule to this Constitution; and s, immediately preceding the date of his application, either- ided in Nigeria for a continuous period of fifteen years; or sided in Nigeria continuously for a period of twelve months, and during the period of twenty years immediately preceding that period of twelve months ha d in Nigeria for periods amounting in the aggregate to not less than fifteen years. Subject to the other provisions of this section, a person shall forfeit forthwith his Nigerian citizenship if, not being a citizen of Nigeria by birth, he acqui ains the citizenship or nationality of a country, other than Nigeria, of which he is not a citizen by birth. ny registration of a person as a citizen of Nigeria or the grant of a certificate of naturalisation to a person who is a citizen of a country other than Nigeria a me of such registration or grant shall, if he is not a citizen by birth of that other country, be conditional upon effective renunciation of the citizenship or nality of that other country within a period of not more than five months from the date of such registration or grant.