This study aims to develop an instructional design whereby ecosystem, biodiversity, and environmental issues are addressed with a holistic approach that provides more efficient teaching as well as to test the effectiveness of this design. A literature review was carried out and need-assessment was firstly made using the Readiness Test. This review and analysis indicated that an instructional design was needed to achieve a better education on ecosystem, biodiversity, and environmental issues. In this regard, two guides in which various methods, techniques, and materials are used were developed for students and teachers on the basis of context-based learning to ensure holistic learning of the ecosystem, biodiversity, and environmental issues. This instructional design was then administered to 165 seventh grade students who formed four experimental groups (N = 82) and four control groups (N = 83) through the non-equivalent control group design, a quasi-experimental design. The achievement test (AT) and environmental attitudes scale (EAS) were administered to the experimental and control group students. Finally, the opinions of the teachers on the teaching process, teaching tools, and materials were obtained by means of the Material Evaluation Form, while the opinions of students on this topic were obtained by means of the Lesson Evaluation Form. The findings obtained from the AT and ETA showed that there were significant differences between the post-test AT and ETA scores in favor of the experimental groups (p<.05). The teachers and students had positive opinions about the instructional design that was developed and implemented by the researcher on the basis of context-based learning. It was concluded that the developed instructional design is more effective in increasing student levels of environmental knowledge and having them develop positive environmental attitudes in comparison to the currently implemented curriculum.