The objective of green tax law is to promote green growth among companies, people and communities as well as environmental preservation. The Malaysian green tax law, however, is more concerned with tax incentives than with tax penalties. Evidence showed most companies in Malaysia are not even aware of the incentive-based tax and thus, do not include them as part of their strategies for environmental sustainability. The green tax penalty has become a popular environmental policy tool for many countries, but not in Malaysia. The Malaysian system of environmental taxes should include the green tax penalty. Therefore, this study aims to identify key drivers for companies to respond to the green tax policy. The study uses institutional theory to explore the driving force of green tax acceptance within companies. Institutional pressure suggests that the three mechanisms of organisational changes are coercive, mimetic, and normative pressures. Coercive pressure stems from political influences and the legitimacy problem; mimetic pressure results from a standard response to uncertainty, and normative pressure is associated with professionalisation. The study utilises the survey questionnaire to identify opinions, experiences and behaviours towards green tax acceptance among manufacturing companies. The population of the study is manufacturing companies and the unit of analysis is managers or accountants who represent the manufacturing companies and members of the Federation of Malaysian Manufacturer (FMM). The outcomes from the study confirmed the institutional theory to support the green tax reform acceptance for companies in Malaysia. The study also develops a green tax model that the government can take into account when enacting green tax reform so that companies can cooperate with Malaysia's green tax law. The study contributes to institutional theory by conceptualising the key drivers of green tax laws among Malaysian companies. The conceptualisation is used to formulate a structural model that explains the key drivers of green tax laws, and the structural model is tested against empirical data. A better understanding of factors influencing green tax policy acceptance is relevant to the government to strengthen the green growth environment and enhance awareness to create a shared responsibility among Malaysian companies.