Manganese ferrite nanoparticles (MnFe2O4 NPs) have significant potential in diverse fields such as environmental remediation and biomedical applications, driven by their chemical stability, magnetic properties, and biocompatibility. This review addresses the gap in sustainable synthesis techniques by focusing on green methods using plant extracts, food waste, and microorganisms as reducing and stabilizing agents for wastewater treatment applications. A total of 35 studies were analyzed and selected based on predefined inclusion criteria such as relevance, methodological rigor, and recency to assess the effectiveness of these approaches in producing MnFe2O4 NPs with enhanced multifunctional properties such as antibacterial, antioxidant, and wastewater treatment capabilities including adsorption, photocatalysis, pollutant transformation, and filtration. Additionally, this review highlights the advantages of green synthesis, including reduced ecological impact, costeffectiveness, and the multifunctional properties of MnFe2O4 NPs. The review also examines the potential of MnFe2O4 NPs in biomedical applications, particularly in medical imaging and targeted drug delivery. The novelty lies in its comprehensive analysis of green synthesis methods and their integration with diverse functional applications. This review provides insight into the emerging trends in MnFe2O4 research, offering directions for future studies focused on optimizing sustainable synthesis strategies and expanding their applications in both environmental and biomedical sectors.