AbstractMegaproject social responsibility (MSR) has received a great deal of attention from both academics and practitioners. However, as a very broad and complex concept, MSR requires an in-depth investigation of its components, driving forces, and contingent factors. Thus, this study aims to explore the climbing process across different levels of MSR from the perspectives of external stakeholders and project complexity. This study first establishes a pyramid framework for analyzing the different components and levels of MSR by leveraging stakeholder theory. Then, drawing upon attention- and capability-based views, theoretical development and empirical analyses are carried out to validate the influence of external stakeholders on participating organizations’ MSR and the moderating effects of project complexity. Using a set of survey data from Chinese megaprojects, the empirical findings demonstrate that the positive influence of external stakeholders and the negative moderating effect of project complexity become salient when ascending the pyramid of MSR. The value of this study lies in the way in which it considers the climbing process based on a hierarchical framework of MSR. The theoretical framework and empirical findings offer both project managers and policy makers with new insights into how to govern the diverse social responsibility issues in megaproject construction and management.