This study examines the influence of corporate governance mechanisms on the adoption of Science-Based Targets and the subsequent impact of SBT adoption on reducing greenhouse gas emissions. It also explores how country-level regulatory governance moderates this relationship. Using data from firms listed in major stock indices across the USA, China, India, Canada, Mexico, Japan, Belgium, France, Germany, Netherlands, Spain, Sweden, and the UK, covering the period from 2018 to 2023, the study finds that strong corporate governance mechanisms—such as board independence, the presence of sustainability committees, and gender diversity—significantly drive SBT adoption. Furthermore, SBT adoption is linked to a significant reduction in GHG emissions, particularly in countries with robust regulatory frameworks, where the negative impact of SBT adoption on emissions is more pronounced. This study contributes to the understanding of corporate climate targets and the effectiveness of SBT in achieving net-zero emissions.