Environmental mainstreaming requires the systematic integration of environmental concerns into all domains of governance, be they at the central level or sectoral, through assimilation into the decisions of institutions that develop national and local policies as well as into the practices of businesses and the value systems of individuals. To make this possible in traditional systems that have a natural tendency to prioritize development objectives over environmental conservation entails the challenge of institutional and cultural change. During these last five decades, Pakistan has gradually developed an adequate framework of environmental governance in the light of international instruments, but integrating environmental considerations into public policy, decision making, and development planning has still not been fully optimized, thus, leaving governance gaps that need to be identified, analyzed, and filled with proper solutions through environmental mainstreaming. The purpose of this qualitative instrumental case study was to analyze the environmental management framework of Pakistan (policies/laws/institutions) through its evolution till its present state, highlight major gaps in this framework that serve as impediments to the goal of environmental mainstreaming and sustainable development in Pakistan, examine the present performance of this framework using case studies, and then to make recommendations to address the gaps based on the lessons learned. In-person interviews of stakeholders from within the environmental management framework of Pakistan as well as a corpus of books, journal articles, reports, and news events informed this study. This study concludes that despite having covered huge grounds over the last five decades, Pakistan, particularly after the 18th Constitutional Amendment which has taken us a few steps back, must improve its overall environmental governance through the creation of inter-ministerial policies, clarification of roles and responsibilities of environmental institutions at all levels along with an improvement in their capacities, adherence to environmental assessments, and through a more focused and effective political will. This cannot be done only at the governmental-level, and must also be a part of the manifestos of political parties and should be a part of the national curriculum from an early stage if the required cultural change is to take place, and there should be more cohesive coordination with NGOs. A lot needs to be done before the environment can be effectively mainstreamed in Pakistan. With the upcoming CPEC mega project which comprises numerous development projects that can have an adverse effect on the human environment in Pakistan, it is hoped that this study will play its part towards a required cultural change in Pakistan that will enable the Government and the people to pass through this promising phase of intensive development while preserving their environment, so that they can truly enjoy the benefits of development and economic prosperity, rather than rue the negative consequences of aggressively pursuing such goals in an ill-planned and irresponsible manner.