Land use land cover change affect the development and the ecosystem in different way. Watersheds in the country are in danger due to continuous threats they are facing. Ribb watershed is endangered due to temporal land use land cover change. Studying land use land cover change and its implication to Ribb dam has a significance of providing evidence for the concerned body to protect and conserve the watershed. This study, therefore, was carried out in Ribb watershed with the major objective of assessing land use land cover dynamics and its implication to the sustainability of Ribb dam. To realize the objectives Landsat images in the year 1973,1986,2001 and 2016 were used and socioeconomic and perception data on watershed land use land cover change was collected from 100 sample households. The analysis of the land use land cover change showed that during the last 44 years cultivated and settlement land and forest cover showed an increment from 26.29% to 54.89% and 9.45% to 12.86% respectively in Ribb watershed. The bushland, grazing land, water body and wetland, however, showed a relative decrement from 29.48% to 17.09%, 21.45% to 12.70%, 4.64% to 2.39% and 8.70% to 0.08% respectively. The socioeconomic analysis result revealed population pressure, poverty, weak policy and institutional enforcement, and tenure insecurity as a major cause for the change in land use land cover. Soil erosion, lack of fuelwood and impact on livelihood are also revealed in the socio-economic analysis as a major consequence of land use land cover change. From the analysis of the results on land use land cover dynamics, it can be concluded that there is a high trend of converting bushlands, grazing lands, and wetlands into cultivated and settlement land in the watershed. Likewise, from the socioeconomic analysis result conclusions can be drawn that population pressure remains the main driver of land use land cover change in the watershed. Based on the study it is recommended that policies related to population, agricultural productivity, and environment with the aim of sustainability should be devised to address the environmental, social and economic problem in the watershed. Keywords: Land use land cover change, watershed, Ribb dam, land degradation, sustainability,