The main objective of this work was to evaluate and characterize graphene oxide-reinforced polyamide 6 nanocomposites and to study the effects of the amount of reinforcement and the cooling rates on nonisothermal crystallization kinetics. A sequence of two processing methods was used to prepare the nanocomposites: first a masterbatch was produced by solution mixing and then diluted in the polyamide 6 (PA6) matrix via melt blending in a twin-screw extruder. Finally, the nanocomposites were submitted to differential scanning calorimetry analyses at different cooling rates in order to evaluate the effect of graphene oxide in the kinetics of crystallization of PA6 for further applications. According to previous theories used to describe the best mechanism of polymer crystallization, it was observed that Mo's theory fitted quite well within the experimental results. Secondary crystallization was strongly favoured in the nanocomposites due to the presence of graphene oxide; however, this nanomaterial decreased the degree of crystallinity of the polymer matrix.