The increasing issue of water pollution by pharmaceuticals, such as amoxicillin, emphasizes the need for sustainableand environmentally friendly solutions that can overcome the shortcomings of traditional methods. Thisstudy concentrates on synthesizing and evaluating new chitosan-olive leaf biomass composites (COLCs) foramoxicillin (AMX) removal from water. A combination of olive leaf biomass (OL biomass), derived from a widelyavailable agricultural waste, with different amounts of chitosan, an aquacultural by-product, led to the developmentof three unique composite adsorbents; 2COLC, 4COLC, and 6COLC. The SEM, BET, EDS, zeta potential,and FTIR analyses were employed to characterize the newly synthesized adsorbents. The COLCs presented ahigher surface area than the OL biomass rising from 10.032 m2/g for the biomass to 14.404 m2/g for 2COLC,31.279 m2/g for 4COLC, and 43.294 m2/g for 6COLC, which increased due to the higher chitosan incorporationimproving the porosity. The adsorption capabilities of the OL biomass and COLCs for AMX were examined. TheOL biomass showed negligible adsorption efficiency while COLCs exhibited enhanced adsorption capacity, whichincreased with increasing chitosan content. The adsorption capacities, as indicated by the Freundlich constantincreased with chitosan content, ranging from 0.011 to 0.04 (mg/g)(L/mg)n for 2COLC and 6COLC, respectively.Thermodynamic studies indicated that the adsorption process for COLCs was spontaneous, endothermic, andthermodynamically favorable. Based on these findings, it can be concluded that the COLCs have the potential asefficient eco-friendly, and sustainable adsorbents for removing pharmaceutical pollutants from water sourcessuch as AMX.