Environmental policy is crucial for defining the scope of conservation and development at the local, national, and international level. Because of its broader framework for balancing conservation and development, environmental policy is considered as the concern of all actors representing multiple disciplines, ranging from environmentalists to development professionals. However, the current practice of environmental policy-making is blamed to be government monolithic and expert-based, which ignored the importance of local communities. In this context, we aimed to analyze the architecture of policy stakeholders and actors’ constellation in the environmental policy-making process in the global south, by taking a case of Nepal. We reviewed national environmental policy milestones (n = 5) and scientific literature (n = 48) and undertook key informant interviews (n = 25) with seven policy stakeholder groups. The developmental history of environmental policy was reviewed from the perspective of policy actors and institutions. We found an increasing involvement of non-governmental (as well as donor) actors in setting the context and framing of the environmental policies. However, the selection of tools of actions of environmental policy was dominated by the discursive sphere of government officials, experts, and international organizations. In addition, implementation mechanisms and institutional arrangements for the transformation of policy objectives into implementation were largely subjugated by government officials, which in turn obstructed in the achievement of the policy outcomes and led to policy failure. We recommend adopting transdisciplinary policy-making approach to solve the complex environmental issues and development imperatives of the country.