With the harsh environmental problems the world is experiencing today, it is high time to enhance environmental education offered by schools. Hence, the main goal of this research study was to determine the effectiveness of the integration of environmental education to formal basic education curriculum in the Educational District I, Schools Division of Bulacan, Philippines. The research utilized the mixed-methods approach through document analysis, interview, SWOT analysis, and survey. Accordingly, important environmental concepts like climate change, waste management, biodiversity, and disaster risk reduction are integrated in the Science curriculum. However, the concept of sustainable development is not yet included in the current curriculum. Co-curricular projects can be tapped to enhance the environmental integration. Likewise, the growing interest in environmental education among members of the community, and the possible cooperation and coordination with different agencies were viewed as opportunities for further improvement. On the other hand, unclear sustainability of environmental projects, and lack of resources were the identified problems. In addition, there may be problems with mobility of various resources managed by residents, continuation of projects due to shifting of interest of community leaders, and sources of fund provided by the community members. Therefore, the inclusion of the concept of sustainable development, and the enhancement of the integration of environmental concepts supplemented by co-curricular projects through the Youth for Environment in Schools Organization (YES-O), and community involvement are highly recommended to every school in the locality.