Norway is a member of the European Economic Area (EEA), so all EEA nationals are free to stay in Norway without a residence permit for up to three months. You must be able to support yourself financially during this period.
If you are an EEA national and plan to stay in Norway for longer than three months, either to work, carry out training or study on a university course, you must register with the police. They will then issue a certificate of registration. Details are available from the Norwegian Directorate of Immigration (UDI). A residence permit is not required.
Restrictions apply to nationals of the new EEA member countries, Bulgaria and Romania. Non-EEA nationals may also be required to apply for a residence permit. Check the Norwegian Directorate of Immigration for further details.