Rock avalanches and related tsunamis represent one of the most serious natural hazards in Norway, and during the last 100 years more than 170 people have lost their lives in western Norway. Large-scale rock-slope failures range from sliding of relatively intact masses of rock, to fully disintegrated rock avalanches. A wide variety of features mirror rock avalanches plunging into valleys or fjords. Bouldery fans, lobes and ridges characterize the proximal parts, while thin debris-flow deposits often occur far beyond this zone. Major deformations of valley-fill and fjord sediments are commonly related to the impact of large volumes of rock. The spatial and temporal pattern of rockavalanche events in Norway demonstrates that such events are common and occur within certain regions, and are important data for evaluating background hazard levels. The mechanisms for occurrence and triggering of rock-slope failures are still uncertain, but seismic ground shaking and creep processes are probably important although, in some areas, effects of glacial unloading during the deglaciation phase cannot be excluded. The geographic concentrations of events indicate that relatively large earthquakes may have played a role as triggering mechanisms. This hypothesis is strengthened by the identification of postglacial faults in two of the rock-failure zones.