The 17 Sustainable Development Goals (SDGs) and 169 targets proposed in 2015 are wide ranging and achieving them before 2030 may require extraordinarily high costs. Prioritizing a more manageable and logical sequence of SDGs targets based on national conditions is critical to reduce the complexity of SDGs, lower costs, ensure transitions are efficient, and accelerate implementation. Researchers have proposed a range of methods to rank the prioritizations of SDGs from different perspectives. Unfortunately, prioritizations of SDGs arising from different methods are not entirely consistent due to the limitations of each method. Therefore, an integrated methodological framework is required to reconcile these inconsistencies. To fill this research gap, we synthesized several methods to create a new composite assessment framework to prioritize SDGs targets. The framework consists of assessment models from three perspectives, including the impact of targets in a network composed of the interactions between targets, the gap between the targets' current and ideal performances, and the urgency of improving participation by government and society in achieving the targets. We then tested the effectiveness of this assessment framework empirically by ranking prioritizations for six targets of SDG 6 (clean water and sanitation) in Southeast Asia. Empirical results show that target 6.5 has the highest priority, followed by targets 6.4 and 6.6, while the lowest ranking target is 6.1. Finally, we outlined the advantages and limitations of each assessment method to assist stakeholders in using and broadening this composite assessment framework in the future.