This study examined the relationship between project planning, risk management, and sustainable development at construction SMEs in Yemen, emphasizing the mediating role of self-efficacy. Using a self-administered survey with a random sampling method, data was collected from 268 construction SMEs employees. Findings demonstrated that project planning management had a significant and positive influence on sustainable development and self-efficacy. Moreover, self-efficacy played a partially mediator role between project planning, risk management, and sustainable development. The result of the study suggests that construction SMEs can enhance project management's positive impact on sustainable development, leading to reduced costs, increased opportunities and profits, and overall organizational success. The research also offers insights into the role of project management and self-efficacy in fostering sustainability within the economy and society, stressing its significance in professional fields and the development of a stable economic and social environment.