This chapter examines methodologies in environmental health research, focusing on their role in addressing the complex interplay between environmental factors and human health. Quantitative approaches, such as systematic reviews and meta-analyses, provide statistical evidence for causal links between exposures and health outcomes, while qualitative methods, including ethnographic studies and interviews, uncover community perspectives and the human dimensions of health. Mixed-method designs combine these approaches, offering comprehensive insights into multifaceted challenges. Ethical considerations, particularly in community-based participatory research (CBPR), are vital to maintaining trust and equity between researchers and communities. As environmental health faces growing threats like pollution, climate changeClimate change, and chemical exposures, evolving methodologies are essential for generating robust evidence and guiding effective interventions. This chapter highlights the importance of refining these approaches to meet emerging challenges, emphasizing adaptability and the integration of implementation science. By showcasing successful case studies, the study underscores the need for strategies prioritizing equity, sustainability, and community empowerment, providing actionable insights for researchers, policymakers, and stakeholders in advancing environmental health research.