Chitosan-like bio-derived polymers possess a number of useful biological properties, but their mechanical and thermal durability needs to be improved to produce performance-driven materials. Inorganic particles are commonly used as fillers to provide reinforcement in polymer matrix. Zeolites are commercially important inorganic materials that are used extensively as adsorbents, ionic exchangers, and catalysts. One form of zeolite, known as molecular sieve 5A, is a Na+ and Ca2+ exchanged zeolite type A with a 1:1 Si:Al ratio. In this study, the role of zeolite as a reinforcing filler in a chitosan/malonic acid composite was investigated. The thermal stability, mechanical properties, and morphology of the chitosan matrix and chemical interactions within the composites were evaluated. It was observed that zeolite significantly improved the tensile strength, modulus, and thermal stability of chitosan and created a fibrous network-like morphology in the chitosan matrix. This study revealed that the inclusion of zeolite molecular sieve 5A improves the performance of chitosan-based biomaterials.