The increasing presence of microplastics (MPs) in aquatic environments has raised significant environmental and public health concerns. MPs, which originate from the degradation of larger plastic waste and various industrial applications, pose severe ecological threats due to their persistence, bioaccumulation, and potential toxicity. Traditional methods for MP removal, such as filtration and coagulation, have proven ineffective or economically unviable at large scales. Biochar, a carbon-rich material derived from the pyrolysis of biomass, has emerged as a sustainable and efficient adsorbent for MPs due to its high surface area, porous structure, and functionalized carbon surface. This review explores the mechanisms governing MP adsorption onto biochar, including hydrophobic interactions, electrostatic forces, and π-π interactions. Additionally, it examines the factors influencing biochar’s adsorption efficiency, such as surface area, functional groups, pyrolysis temperature, and environmental conditions. The study highlights that modified biochar, particularly those activated with metal ions or nanomaterials, exhibits enhanced MP removal efficiency. Furthermore, the environmental and economic benefits of biochar, including its role in carbon sequestration and waste valorization, make it a viable alternative for large-scale water treatment applications. Despite its advantages, challenges such as biochar stability, desorption risks, and regeneration methods require further research. This study underscores the potential of biochar as an innovative and sustainable solution for mitigating plastic pollution in aquatic ecosystems.