The emergence of environmental contaminants (ECs) either from natural or anthropogenic sources is considered a critical threat to the various components of the ecosystems. Therefore eco-friendly, innovative, and practical approaches for the remediation of ECs are needed toward sustainable environmental pollution management. Among the innovative techniques, nanomaterials are robust and contemporary research tools to combat the ECs in various ecological components. However, the preparation of desired nanoparticles (NPs) through physical and chemical means is discouraged because of the requirement of high energy inputs and adverse impacts on the environment and associated biota. Thus a keen interest of the scientific community has been growing toward sustainable production of NPs using innovative microbial techniques and their practical application. Among the huge diversity in fungi, some genera are considered as potential candidates for NPs synthesis because of their higher capabilities of bioaccumulation and secretion of large amounts of proteins and other biomolecules. These mycosynthesized NPs have exhibited excellent performances to adsorb or decontaminate various emerging ECs such as hazardous chemical dyes and heavy metals. Mycosynthesized NPs can appreciably degrade the toxicity associated with heavy metals (approximately 90%) and dyes and have shown high promise for remediation of ECs. This review updates knowledge and research progress concerning the synthesis of NPs using fungal species and discusses the future application of mycosynthesized NPs in remediation of ECs as nano-based green remediation.