International Driving Permit in Norway

You are only asked to show your International Driver's Permit if you are stopped by the police. Sorry, I don't know about Norway.

I always got one for previous trips and was never asked for it.

I rented a car in Norway for one day and wasn't asked for it there either, which is good because I didn't have one.

I found this at http://relocation.no/expat-communities/national-information/driving-in-norway/:

You need a full, valid driver’s license issued in your country of
residence. If your license is not issued by an EC/ECA country, an
International Driver’s Permit (IDP) may be required.

The IDP is just a translation of your home license in multiple languages and in the Geneva Convention format. A rental company staff will likely not ask for it, since they are already familiar with American and Canadian licenses. But what if you are pulled over by a policeman? What does the motor vehicle code of the country you are driving say? Most European countries require it unless your state is part of the EU or EEA, or there is a reciprocity agreement in place or if it is issued in the Geneva Convention format. Is your State in the EU or EEA? If not does your State have a reciprocity agreement with the country you will be driving? Is the license issued by your state issued in the format established by the Geneva Convention? If you don’t know all the answers it is easier to get an IDP at the AAA.

Before we went to Norway last July I did exactly what Roberto is suggesting. I found the Norwegian motor vehicle agency website and read carefully their policy for nonEU visitors and their drivers licenses. Based on what I saw I understood that Norway did not require an IDP and I did not bother to get one. End of story. I have no idea if the policy is still the same but it was very easy to tell at that time since it was written in perfect English.

In Norway you can use your Tennessee license for up to 3 months if it is not expired. Norway does not require an IDP from US drivers.