<p>The poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)/graphene oxide (GO) nanocomposites were produced using the melt compounding technique with the aid of a twin-screw extruder. The main goal of this study was to assess the influence of GO addition on the thermal and mechanical properties of biodegradable polymeric nanocomposites based on PHBV. Nanocomposites were produced with three GO contents (0.1 wt%, 0.3 wt%, and 0.5 wt%). All nanocomposites showed similarities to the neat polymer in their chemical structure and thermal stability. However, a more significant interaction between the filler and matrix was observed through Raman spectroscopy for the nanocomposite with the lower concentration. All nanocomposites showed similar crystallinities but with increased crystallization temperatures and a reduction in the time required for crystallization when compared to neat PHBV, indicating the nucleating effect of GO. The most considerable mechanical improvement was found for the nanocomposites with lower GO content (0.1 wt%). The impact strength for this nanocomposite increased by 25%. Also, it was possible to improve 18%, 72%, and 123% in tensile strength, elongation at break, and toughness, respectively. This behavior was associated, through field emission gun scanning electron microscopy (FEG-SEM), with a rougher appearance on the fracture surface compared to the other compositions. The presence of GO leads to a reduction in Mv because of the intensified degradation process during extrusion; however, this decrease in molecular weight was not enough to adversely affect the biodegradability of PHBV. These are significant results when considering that the technique used to obtain the nanocomposites was mixing in the molten state, one of the most essential techniques for the possibility of an industrial application.</p>