The law regulating citizenship in Sweden is based on the Swedish Citizenship Act of 2001, as last amended in 2014. Swedish citizenship is primarily based on the principle of ius sanguinis, meaning that citizenship can be acquired by birth to at least one Swedish parent, irrespective of the place of birth. Citizenship may also be acquired through adoption if the child is under 12 years of age, by marriage, naturalisation after a residency period or by notification.
As of 2001 dual citizenship is accepted in Sweden without the need to renounce Swedish citizenship. Thus, a Swedish national acquiring a foreign citizenship does not lose Swedish citizenship and vice-versa, foreigners seeking naturalisation to acquire Swedish citizenship, are not required to renounce their existing nationality. The Swedish law does not specify any consequences in relation to the registration or renunciation of original citizenship and dual citizenship is allowed without any special conditions.