Born between 1 July 1979 and 1 August 2006
If you were born between 1 July 1979 and 1 August 2006, you became Norwegian at birth provided that your mother was Norwegian when you were born. You also became Norwegian if your father was Norwegian when you were born, provided that your father was married to your mother when you were born. If only your father was Norwegian and your parents married after you were born, but before you reached the age of 18, and before 31 August 2006, you became Norwegian from the point in time your parents became married.
If your father was Norwegian and not married to your mother, your parents may submit notification of citizenship before you reach the age of 18 (notification of citizenship). This became allowed beginning in October 1999. If you have a letter of decision or a certificate attesting that you became Norwegian through notification, then you became Norwegian when the notification was received by the Norwegian authorities. If you have not reached the age of 18 yet, your parents may still submit a notification of citizenship.
You must have a birth certificate and be able to document that at least one of your parents was Norwegian when you were born.
If your father or both your parents were Norwegian you must submit your parents’ marriage certificate (applies whether they were married when you were born or if they married before you reached the age of 18).
If you became Norwegian through notification, you must submit a certificate of Norwegian citizenship.
If you no longer have the certificate of Norwegian citizenship, you may contact the County Governor, the National Archives of Norway or UDI.
"The Norwegian Nationality Act of 8 December 1950” (with amendments to the wording in Section 1)".
Regarding notification of citizenship by father, see «Guidelines for processing citizenship cases in pursuance of the Norwegian Nationality Act (sections 1a and 2a) (external website)».