This study explored the potential of converting water hyacinth biomass into bio-oil and biochar through a continuous pyrolysis process in a rotary kiln reactor at varying temperatures (400, 500, and 600 ºC). The results indicated that the highest yield of the liquid fraction was obtained at 500 ºC (42.11%), while 400 and 600 ºC resulted in higher production of biochar and pyrolytic gas. The bio-oils obtained from the pyrolysis process had an average calorific value of 68% compared to petroleum-derived fuels and were rich in acids, alcohols, phenols, and sugar derivatives. Comprehensive characterization of the bio-oil produced at 500 ºC using APCI(−)-FT-Orbitrap MS analysis revealed its high oxygen and nitrogen content. The pyrolysis temperature also increased the aromaticity of biochar, making it a potentially valuable material for agricultural use as a soil amendment and for carbon sequestration. These findings demonstrate the potential of rotary kiln reactor pyrolysis for producing value-added products from water hyacinth biomass.