I'm a Norwegian pensioner in Portugal — does Norway's 15% withholding tax on my pension apply?

For private and occupational pensions, usually no: the Norway–Portugal treaty (Article 18) gives the taxing right to your residence state, so with a Portuguese treaty-residency certificate you can have the Norwegian kildeskatt reduced or refunded. Exceptions matter: government-service pensions stay taxable in Norway, and disability/social-security benefits follow their own track. The common failure is documentation — the exemption is claimed, not automatic. And note: IFICI (NHR 2.0) excludes pensions, so Portugal taxes them at ordinary progressive rates.