The origin of Pacific decadal climate variability is investigated in a coupled ocean-atmosphere general circulation model. The impact of regional ocean-atmosphere coupling and oceanic teleconnection on decadal variability is evaluated by performing a set of specifically designed experiments. It is found that decadal variability in the tropical and North Pacific originates predominantly from local coupled ocean-atmosphere processes within the tropical and North Pacific region, respectively. Furthermore, tropical Pacific decadal variability appears to be associated with higher baroclinic modes and can be enhanced substantially by extratropical-tropical oceanic teleconnection.