This chapter provides an overview of piezoelectric vibrational energy harvesting and outlines significant advances in polymer composites for harvesting applications. The piezoelectric phenomenon is described and relevant equations are provided and explained. Several prominent types of piezoelectric materials are discussed, followed by a description of the advances made through the combination of polymers and particles to create piezoelectric composites. An in-depth description detailing how to significantly increase the piezoelectricity of poly(vinylidene difluoride) through the incorporation of carbon nanomaterials such as single-walled nanotubes (SWNTs) and Buckminster fullerenes (C60) is given, followed by the description of a new, lead-free ceramic material that is a promising candidate for use in non-toxic polymer composites. Finally, a comprehensive description of the design and modeling of piezoelectric polymer composite bimorphs for vibrational energy harvesting is provided.