Recently, Egypt has faced unprecedented development with rapid urban and infrastructure expansion. Vast areas of Egypt are underlain by karst rocks (carbonate and evaporite). Highways and roads constructed along these karst areas are susceptible to slope stability problems. Various factors could trigger different landslides along the carbonate rock cliffs and slopes. Hence, urgent actions need to be considered to understand the landslide mechanisms that could occur along these cliffs and slopes. Carbonate rock cliffs and slopes along with some highways in Sohag-Assiut area, Egypt, were chosen as a case study in this work. Field and laboratory investigations were carried out as tools in understanding and identifying these failure mechanisms. In addition, remote sensing high-resolution images were applied to help in identifying different features, causing slope instability. Our finding indicated that five landslide mechanisms in carbonate rock cliffs and slopes were identified and categorized. These five slope instability mechanisms are including collapses of weak materials from filled caves, the breakdown of caves, instability due to differential erosions, dissolution along discontinuities, and sliding along weak surfaces. This study could help the decision-makers and planners to understand the causes of slope instability problems, to maintain the sustainability of the infrastructure, and to design appropriate prevention and remediation measures to avoid future problems.