The Intergovernmental Panel on Climate Change recently stated that a swift ecological transition in transport, energy, and construction is required to reach the global emission reduction target. Around 40% of global emissions come from residential and commercial buildings. Therefore, this study developed a green building adoption model based on the Unified Theory of Acceptance and Use of Technology, which encourages firms to implement these novel green building technologies. For this, a survey of 333 respondents from Pakistani construction firms was conducted, and Partial Least Square Structural Equation Modeling approach was applied to validate the study's hypotheses. The findings showed that green building adoption provided invaluable insight by showing the strong associations between green building environmental concern, green building performance expectancy, green building effort expectancy, green building social influence, and green building innovation cost with green building behavioral intentions. Likewise, the findings also showed that green building behavioral intentions play a significant mediating role between the adoption of green buildings and its factors. The findings from this study suggest that intentions to engage in green building activities have a strong direct and mediating effect on green building adoption. Furthermore, the moderating effect of firm size demonstrated the significant differences between small, medium, and large firms size. Based on the study’ findings, the green building adoption model provided novel insights for governments and concerned stakeholders, including construction firms, to adopt green buildings for carbon neutrality in this era of climate emergency.