This study explored the relationship between scientific context (SC), scientific reasoning (SR), and scientific behaviour (SB) across the environmental principles to show their significance as essential scientific competencies in the development of environmental programmes in the Philippine K-12 curriculum in a process where environmental education has a key role to play. One hundred and seventy-seven high school students from Bongabong, Oriental Mindoro in the Philippines were selected through the cluster purposive probabilistic sampling method. A descriptive normative survey method of research was employed in this study. The students' SC had a high relationship with their SR, which is a direct indicator of SB. This was a sign that SC, SR, and SB all work together in a continuous way. Findings of this study will serve as baseline information for the framework of environmental education programmes through science, in the K-12 Philippine Science curriculum. So, when students learn things in the real world, they gain environmental effect, which is thought to be a key reason why people act in ways that are good for the environment and an important goal of environmental education.