Slope stability problems in soils underlie most of the landslides that cause losses of human and property in the world. The stability of natural or man-made slopes in soils is an important topic that requires great attention while site exploring, testing, modelling and analyzing. Engineering geology and geotechnical engineering interdisciplinary team work is essential to achieve a sufficient understanding of site geology and the behavior of soil. The developments of urban areas require new sites for settlement. Soil structure interaction in slopes requires more sophisticated numerical analysis methods to develop. This section particularly summarizes the factors cause a slope to fail. In addition, site exploration steps, in-situ and laboratory test methods were mentioned. Slope stability analysis methods such as LEM, FEM, DEM, BEM were discussed in details. The developments of empirical or statistical regional approaches were stated. Remediation techniques were discussed regarding the construction costs. Finally, the necessity of further studies in numerical modelling was emphasized.