Abstarct: The aim of this study was to develop a sunflower oil in water Pickering emulsion stabilized with chitosan (CS)-stearic acid (SA) nanogel, and to investigate its oxidative stability along with peppermint essential oil (PEO). In the first step, by using different proportions of SA to CS, CS-SA nanogels were prepared by self-assembled method. The results of scanning electron microscopy (SEM) images showed that by increasing the ratio of SA to CS, the uniformity of particles was increased. Then, the effect of pH (2, 5, 8 and 10), SA to CS (0, 25, 50 and 75%) and oil ratio (100, 200, 300 and 400 µl) on the size of oil droplets and the stability of the emulsions after the first and seventh day of production were investigated. The results showed that emulsions with pH 8, SA to CS ratio of 50% and oil ratio of 200 µl had the highest stability and minimum droplet size. In the following, the oxidative stability of the Pickering emulsion (pH 8, SA-to-CS ratio of 50% and oil ratio of 200), along with the PEO (200 and 1000 ppm) in both shell and core of encapsulated sunflower oil as well as an emulsion stabilized with tween 80 during 20 days at 40 ° C using peroxide and thiobarbituric acid tests was evaluated. The results of oxidative stability indicated that Pickering emulsion had more oxidative stability than emulsion stabilized by tween 80. Also, the results showed that the application of PEO in the shell of oil droplets caused an increase in oxidative and physical stability compared to the oil core.