In Slovenia, mass movements are not only a threat to the population, but also a major environmental and social science challenge. Lithologically heterogeneous areas have been found to be problematic, and the Miocene Slovenj Gradec basin (in northeast Slovenia) is one such area. For this area, we developed landslide and rockfall susceptibility maps based on detailed geological research combined with statistical modeling schemes. Crucial factors include lithological composition, land use, geological structural elements, slope curvature, aspect and inclination, and bed dipping. The approach taken in the development of mass movement susceptibility maps presented here is transferable to other areas defined by heterogeneous lithology. Such maps could prove useful spatial planning, forestry, environmental protection, landscape architecture, and other fields.