Wood flour, which is produced during the processing of wood, is often used as a filler in polymer composites. However, its hydrophobicity and poor adhesion to polymer matrices can limit its effectiveness in these applications. To address this, the wood flour was modified in three different ways using (3-aminopropyl)triethoxysilane (APTES). The resulting modified wood flours were then incorporated into a polymer matrix and analyzed. This study aimed to evaluate the impact of these modifications on the vulcanization, rheological, and mechanical properties of polymer composites. The effect of the silanization reaction on the modified wood flour forms was also observed. The results indicate that modifying wood flour with APTES significantly affects its interaction with the polymer matrix, thereby improving selected composite properties. Comparing the different modification methods enabled the most effective treatment of wood flour to be identified, which optimally enhances the properties of the polymer matrix. This study provides valuable information for developing environmentally friendly composite materials based on wood flour. Due to its versatility and environmental benefits, wood flour is a valuable material with a wide range of potential applications.