The conversion of biomass waste into adsorbents offers a sustainable approach for water treatment. This study aims to investigate the effect of pyrolysis temperature at 400, 600, and 800 ℃ on biochar derived from palm kernel shell for methylene blue (MB) adsorption. Biochar samples were characterized using yield determination, Xray fluorescence (XRF), CHNS elemental analysis, scanning electron microscopy (SEM), and X-ray diffraction (XRD). Adsorption performance was evaluated at different MB concentrations (10, 30, and 50 ppm) and adsorbent dosages (0.05, 0.15, and 0.25 g). The biochar yield decreased from 76.2% at 400 ℃ to 72.8% at 600 ℃ and 57.2% at 800 ℃, while conversion increased from 23.8% to 42.8%. CHNS analysis revealed carbon enrichment and increased aromaticity with increasing temperature, whereas SEM and XRD analyses confirmed significant morphological and structural transformations during carbonization. Adsorption results showed that MB removal efficiency (RE) decreased slightly with increasing MB concentration but improved with increasing adsorbent dosage. Biochar produced at 600 ℃ demonstrated the best adsorption performance, achieving a maximum RE of 68.09% at an adsorbent dosage of 0.25 g. These findings suggest that an optimum pyrolysis temperature is required to balance biochar yield, carbonization, and adsorption effectiveness.