<p>The assessment of the social impacts of disasters is significant to the decision-making process in public policies for disaster risk reduction. For this reason, the present work proposes to join the Social Impact Assessment (SIA) and Social Life Cycle Assessment (sLCA) methodologies to obtain the most important aspects that the consequences of landslide disasters have on a population to permit a global quantitative measurement of the impacts. A literature review indicated the categories of impact aiming to build the social indicators needed to assess the disaster impact, they were political, educational, economic, infrastructure, environmental, social, services, and health. An Analytic Hierarchy Process (AHP) study was designed to evaluate the importance of the categories and subcategories considered. To achieve this AHP analysis, a team of 24 specialists was considered to accomplish a pair-wise comparison between the categories to judge the respective importance. For the eight categories considered, the study concluded that the health, environmental, economic, and social categories are the ones that deserve more attention when considering landslide disaster impacts. The contribution of this research is the design of a quantitative method to assess the impact of landslide disasters by defining impact categories and indicators. A disaster impact index was defined (DII), based on these parameters, making it possible to assess and hierarchize disaster impacts. It promotes a better decision-making process for reconstruction projects in affected municipalities and the improvement of transparency of disaster risk governance.</p>