Illegal land use inhibits available land for renewable resource development and hinders a just energy transition, posing a significant challenge to sustainability. This article utilizes the TOE (Technology, Organization, Environment) framework to examine the impact of under-regulation on illegal land use in China. By employing a multidisciplinary approach, the study navigates the complexities of unscrupulous land practices and uncovers their socio-economic and environmental implications. Findings from panel data analysis covering the period of 1999 to 2009 reveal several key insights. Firstly, inadequate technology hampers regulators' ability to detect illegal activities, leading to an increase in the area of illegal land use. Secondly, a high turnover rate of regulatory officers is linked to lower levels of punishment for illegal land use, thereby contributing to an expansion of illegal land use. Thirdly, a permissive government-business environment hinders the effective enforcement of the land approval system, thereby restraining the prevention of illegal land use. Through case studies and policy analyses, the research aims to reveal the challenges and obstacles arising from illegal land use in transitioning to a cleaner energy future. The findings contribute to a nuanced understanding of the obstacles posed by illegal land use, offering insights to policymakers, industry stakeholders, and advocates in navigating towards a more equitable and sustainable energy landscape.