Nanomaterials have excellent functional properties with enhanced surface-to-volume ratio and, therefore suitable for diversified applications. In order to study and understand the physical and chemical properties of nanocatalysts, various characterization tools are employed through imaging and analysis by spectroscopy and microscopy. Therefore, this chapter will provide an overview of commonly employed characterization tools in determining the morphological, chemical, physical, and structural properties of nanoparticles and nanostructured materials. The techniques for analyzing the topology of nanocatalysts, including Field Emission Scanning Electron Microscopy (FESEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray spectroscopy (EDS), Fourier Transform Infrared Spectroscopy (FTIR), Dynamic Light Scattering (DLS), Atomic Force Microscopy (AFM), UV–Visible spectroscopy, Zeta potential measurements, X-Ray Florescence (XRF) are described. Additionally, the microstructural investigation using X-ray diffraction (XRD) is also included in this chapter.