Polymeric nanocapsules consist of a core surrounded by a thin layer of polymer. Several bioactive compounds can be encapsulated for the controlled and target delivery, including food, cosmetics and drugs. For the synthesis of the nanocapsules, miniemulsion polymerization appears to be promising, since the nanocapsules can be obtained from only one step with high encapsulation efficiency. Stable miniemulsions can be obtained choosing an appropriate co-stabilizer. Many works show hexadecane as an efficient co-stabilizer. However, the pursuit for different, preferably biodegradable, co-stabilizers has increased in order to enhance their applicability in different fields. Some works have shown the successful use of vegetable oils as co-stabilizer. The aim of this present work was to study the kinetics of methyl methacrylate miniemulsion polymerization using argan oil as a co-stabilizer. Besides acting as a co-stabilizer, argan oil presents antioxidant and antithrombotic activities. The results show that due to the double bonds presented in the argan oil, the polymerization reaction is slower when compared to hexadecane. Besides the kinetics, it was verified that argan oil acts in the stability of the miniemulsion polymerization, since the average particle size did not increase over the reaction, preventing the system from monomer diffusion and coalescence.