Biochar/Layered double hydroxide composites are of priority when dealing with wastewater treatment since they are of low cost and have high effects. The incorporation of rare earth elements into Biochar/LDH further enhances its adsorption performance and magnetic ability toward pollutant removal. Such Lanthanide-based layered double hydroxide (LDH) biochar nanocomposites have gained considerable attention as sustainable materials for advanced wastewater treatment due to their exclusive physiochemical properties, extensive surface area, adsorption characteristics, and environmental compatibility. The review provides insight into current progressions in the formation, analysis, and application of LDH biochar nanocomposites in wastewater treatment. Key aspects such as the inclusion of lanthanide elements, optimization of synthesis methods, and enhancement of adsorption capacities are discussed. In addition, the mechanisms underlying pollutant removal, including adsorption, ion exchange, and photo-catalytic degradation, are elucidated. The review also highlights the challenges and future perspectives in the development and scale-up of LDH biochar nanocomposites for sustainable wastewater treatment solutions. Overall, this review facilitates scientific discovery for researchers and practitioners in the field of ecological engineering seeking to use the potential of lanthanide-based LDH biochar nanocomposites for efficient wastewater remediation.