The unique properties of chitosan make it stand out as an ideal adjuvant candidate. However, the low solubility of chitosan in non-acidic aqueous media limits its use as an adjuvant. In this study, a method was offered to overcome this limitation, without any structural modifications of chitosan. The proposed method incorporated the preparation of Pickering emulsions via self-aggregation of the chitosan particles. As a model for this preparation, a w/o/w emulsion formulation of the foot-and-mouth disease (FMD) vaccine was utilized. Two vaccine formulations, with and without chitosan, were prepared and compared regarding their physicochemical properties. Laboratory animal (guinea pigs) trials were conducted to reveal the immune response in terms of neutralizing antibody levels. The sera were collected from two animal groups and tested for neutralizing antibody levels using a homologous virus neutralization test (VNT). Statistical analyses of the test results were performed at a 5% significance level using Quasi-Least Squares Regression (QLS). The incorporation of chitosan into the w/o/w vaccine formulation did not compromise the physicochemical properties of the emulsion. Statistical analysis reveals that the presence of chitosan enhances the antibody response. The effect of time and group on the neutralizing antibody titer levels (NATL) was found to be significant (p < 0.05). Our results suggest that the limitation of the use of chitosan as an adjuvant could be overcome by the Pickering emulsion preparation approach, without a need for further structural modifications. The presence of chitosan in such a vaccine formulation could enhance the immune response.