Nanocomposite materials, with their distinctive physicochemical properties like high surface area, reactivity, and selectivity, have emerged as promising agents for remediating hazardous pollutants. Comprising nanoparticles ranging from 1 to 100 nm dispersed in organic, inorganic, or hybrid matrices, these materials require meticulous consideration of surface chemistry and interactions to optimize performance. Tailoring nanocomposites for specific applications involves adjusting composition, structure, and properties. Carbon-based, metal-based, and metal oxide-based nanocomposites have been developed and applied effectively in the environmental remediation of heavy metals, organic pollutants, and dyes. This chapter delves into the mechanisms underlying pollutant removal, addressing the challenges and opportunities in nanocomposite development for environmental remediation. The exploration extends to the intricate interplay between nanocomposite properties and pollutant removal mechanisms, particularly in the context of heavy metals, organic pollutants, and dyes. The chapter culminates by reflecting on the future prospects of nanocomposite materials, envisioning their role in advancing technologies for environmental remediation. The versatility and tunability of nanocomposites position them as pivotal contributors to the ongoing quest for sustainable solutions in mitigating environmental pollution.