PolymerPolymer is a versatile material known for its low cost, light weight, flexibility, ease of processing, and dimensional properties. However, the mechanical characteristics of polymeric materials often need to be improved for engineering applications. As a result, research has focused on developing new and enhanced polymeric materials with EMIElectromagnetic Interference (EMI) shielding properties. PolymerPolymer blending has been a common approach to creating materials with unique characteristics. Yet, like pure polymersPolymer, these blendsBlends exhibit insufficient physical properties for engineering use. Over the past few decades, studies have explored the incorporation of various fillers and nanofillers into polymerPolymer matrices. The inclusion of nanofillers has resulted in materials that are cost-effective, lightweight, easy to process, and possess desirable mechanical properties. This chapter discusses carbon-basedCarbon-Based nanofillers, which can replace the conventional metal-based fillers frequently used in EMIElectromagnetic Interference (EMI) shielding applications.