In the recent past, piezoelectric materials established on polymers and their composites have acquired incredible interests due to their unique properties as well as multipurpose applications. Polymers have recognizable advantages over ceramics in specific applications in terms of their easy processing ability at low temperatures, low density, low stiffness, flexibility, and mechanical robustness, such as toughness and high strains to failure. They are also advantageous in terms of biocompatibility for implantable harvesters and sensors. Polymer-based piezoelectric materials have demonstrated versatile applications in smart and multifunctional systems such as sensors, actuators, transducers, energy harvesting, and storage devices, in the form of fibers, foams, thin films, textiles, and coatings. The piezo-composite is a polymeric material in which engrafted organic/inorganic fillers are used and gives raise exciting properties and demonstrates outstanding potentiality that is promising for developing energy materials for advanced smart electronics. In this chapter, first of all a brief introduction of piezoelectricity is discussed, after that an overview of piezoelectric polymers and composites is presented along with their recent developments, properties, and advanced multifunctional applications. Eventually, a conclusion and several future perspectives of piezoelectric polymers and their composites as energy materials are demonstrated.