The aim of this study was to evaluate the effect of the addition of the plasticizer triethyl citrate (TEC) combined with clay (montmorillonite – MMT and halloysite – HNT) on the morphology and mechanical properties of poly(hydroxybutyrate-co-hydroxyvalerate). The compositions were prepared with 10 wt% TEC and 3 wt% clay by melt processing in an internal mixer at 170 °C and 100 rpm for 5 min. The clay was previously dispersed in the plasticizer by magnetic stirring for 4 h. For comparison, one sample was prepared by the direct mixture of the clay and plasticizer during melt compounding. From scanning electron microscopy (SEM) images, it was possible to observe that the nanocomposites prepared with previously dispersed clay presented a better distribution of nanoparticles in the PHBV matrix. For the system obtained by direct mixture, energy dispersion spectroscopy (EDS) results evidenced the presence of some tactoids. Dynamic-mechanical analysis (DMA) evidenced the plasticizing effect of TEC, with a general decrease about 15°C in the glass transition temperature and a reduction in the storage modulus at room temperature of the nanocomposites, compared to the neat PHBV. Exudation tests evidenced the good interaction between the plasticizer and the polymer. There was a general increase in the impact strength, but it was dependent on the degree of dispersion of the nanoparticles in the polymer matrix. When previously dispersed in the plasticizer, the addition of clay promoted an increase of 119% and 135% in impact strength when using MMT and HNT, respectively. When directly blended, the increase was of 82%. In general, the results showed that the combination between plasticizer and clay is a viable alternative to the use of this polymer in various industrial applications.