The widespread development of hydropower dams has led to involuntary displacement, which has become a significant global issue. In Vietnam, around 70,000 households were displaced in 2020, causing uncertainty and social disruption. The aim of this study is to analyze the effects of resettlement on the livelihood and food security of displaced households, explore the underlying challenges and causes of these effects, and recommend policy implications for sustainable livelihood development and poverty alleviation. This study conducted a decade-long sociological examination of three displaced communities in Thua Thien Hue province, Vietnam. Our research reveals that resettled households are unable to regain their former standard of living due to the loss of cultivated land and restricted access to public property, which exacerbates food insecurity. Unemployment, illiteracy, and low income further perpetuate poverty. These findings highlight the deficiencies in current policies and planning approaches and call for implementing socially responsible resettlement processes guided by principles of equity. Addressing the inequalities arising from displacement and enabling affected communities to participate in growth is economically justified and morally imperative.