As individuals’ living standards increase, the needs for the well-being of individuals are becoming more complicated, especially among children. Even though multidimensional methods for researching child well-being in Vietnam have made some progress, analyses of single dimensions of child well-being remain common. The research analyzes the relationship between social assistance, household welfare and child well-being on both objective and subjective aspects by applying Structural Equation Modeling (SEM) through the secondary data collected from the Vietnam Sustainable Development Goal Indicators for Children and Women survey in the period 2020-2021 by the General Statistics Office (GSO) and the United Nations International Children's Emergency Fund (UNICEF) of Vietnam. The research results emphasize the mediating role of household welfare as high social assistance increases household welfare, thereby improving child well-being in Vietnam. Based on the research results, the research proposes several recommendations for the management and improvement of social assistance programs, thereby improving child well-being in Vietnam.