In this study, polyurethane (PU) composites have been produced with oil palm empty fruit bunch (EFB) and polyethylene glycol (PEG), molecular weight (MW) of 200 (PEG200), 400 (PEG400), and polypropylene glycol (PPG) with MW of 400 (PPG400) used as polyols. The effect of isocyanate (NCO)/hydroxyl (OH) ratio and PPG400/PEG400 ratio on the impact strength, dimensional stability (immersion test), and thermal behavior were investigated. The study revealed that as the NCO/OH ratio was increased, the impact strength increased, and the absorption and swelling of the composites either in water or dimethylformamide (DMF) decreased. The decrease in the onset and peak temperatures, and the increase in the enthalpy as the NCO/OH ratio was increased from 0.8 to 1.1 were attributed to the disruption of crystalline region due to the occurrence of cross‐linking. As for NCO/OH ratio of 1.1 onward, the increase in onset and peak temperatures were due to the increase in the degree of cross‐linking. On the other hand, the decrease in the enthalpy was due to the formation of allophanates. Thermal behavior of the composites made from the glycol mixture was predominantly influenced by the PPG400.