The development of new biodegradable composites with superior properties is an attractive approach to develop environmentally friendly materials with new potential applications. In this work, we prepared and characterized PHB filaments with different concentrations of ZnO particles (from 0.5 up to 16 wt%) to evaluate this mixture's effect on the physico-chemical, thermal properties, and morphological biofilament characteristics. The FTIR and Raman results indicated a possible chemical interaction between the ZnO and PHB, altering the helical polymeric and crystalline structure. The ZnO particles increased the composites' thermal stability, mainly at higher filler contents, confirmed