Effects of acetylation, plasticization (ethylene glycol) and filler(kaolinite) reinforcement on the moisture and water absorption characteristics of cassava starch films were investigated at various levels of plasticizer concentration (2, 3, 4, 5 g/100 g of starch), and kaolinite (0, 0.5g, 1 g/ 100 g of starch). The combined effects of the plasticizer and filler concentration on mechanical properties were also examined. Acetylation reduced the gelatinization temperature of native starch from 65 °C to 51 °C improving the processability and flexibility of the films. Moisture absorption of the films increased with higher ethylene glycol content, reaching 38.5% in films with 5 g of ethylene glycol and 0.5 g of kaolinite. Water absorption followed a similar trend, with the highest absorption of 38.3% observed in films with 5 g ethylene glycol. The tensile strength of the films wassignificantly improved by kaolinite reinforcement, with films containing 1 g of kaolinite exhibiting the highest tensile strength of 10.74 MPa. However, higher plasticizer content reduced tensile strength, indicating a trade-off between flexibility and strength. These results demonstrated the optimal combination of acetylation, plasticization, and kaolinite reinforcement to effectively balance flexibility, strength and resistance to moisture and water.