A large number of landslides were triggered by the 2008 Mw 7.9 Wenchuan earthquake, which was accompanied by 270 km of surface rupture along the Longmenshan fault at the eastern margin of the Tibetan Plateau. The landslides were strongly controlled by geology, geomorphology, and earthquake shaking. They were concentrated on the hanging walls of the fault ruptures, and their directions seem to have been affected by the directivity of seismic waves. Landslides were also concentrated within the inner gorge of Minjian River. Carbonate rocks failed preferentially, probably due to their low shear resistance, caused in part by dissolution. A power function defines the relationship between the cumulative number of landslides and landslide area. The largest landslide, with an estimated volume of 0.8 km3, occurred on a cataclinal slope of carbonate rocks and was preceded by slow gravitational slope deformation. The second-largest landslide occurred in carbonate rocks on an undercut slope. Another large landslide had a long runout due to liquefaction and entrainment of sandy valley-bottom sediments. More than 800 of the landslides triggered by the earthquake blocked watercourses and impounded lakes.