This review discusses the synergistic effects of hybrid fillers in emerging composite and nanocomposite materials. Hybrid fillers, which combine organic and inorganic components, offer enhanced mechanical, thermal, and electrical properties compared to single fillers. The integration of hybrid fillers into polymer matrices improves the performance of composites and nanocomposites through synergistic interactions between the fillers and the polymer matrix. The review highlights recent advancements in the use of hybrid fillers, including their effects on mechanical, thermal, and electrical properties, as well as their applications in various fields. It also examines the challenges and opportunities associated with the use of hybrid fillers, emphasizing the need for further research in this area. The review covers the use of various fillers, including organic–inorganic, nano–micro, and bio-based fillers, and discusses their synergistic interactions. The study also explores the potential of hybrid fillers in applications such as energy storage, electromagnetic interference shielding, and flexible electronics. The review concludes with a summary of the current state of research and recommendations for future studies in this rapidly evolving field of materials science.This review discusses the synergistic effects of hybrid fillers in emerging composite and nanocomposite materials. Hybrid fillers, which combine organic and inorganic components, offer enhanced mechanical, thermal, and electrical properties compared to single fillers. The integration of hybrid fillers into polymer matrices improves the performance of composites and nanocomposites through synergistic interactions between the fillers and the polymer matrix. The review highlights recent advancements in the use of hybrid fillers, including their effects on mechanical, thermal, and electrical properties, as well as their applications in various fields. It also examines the challenges and opportunities associated with the use of hybrid fillers, emphasizing the need for further research in this area. The review covers the use of various fillers, including organic–inorganic, nano–micro, and bio-based fillers, and discusses their synergistic interactions. The study also explores the potential of hybrid fillers in applications such as energy storage, electromagnetic interference shielding, and flexible electronics. The review concludes with a summary of the current state of research and recommendations for future studies in this rapidly evolving field of materials science.