Carbon dots (CDs) are a class of carbon nanomaterials smaller than 10 nm. Thanks to their functionalization, high surface area, biocompatibility, stability, and green, cost-effective production methods, they have been effectively utilized in various applications, such as drug delivery, bioimaging, sensors, and effluent treatments. Although these properties make CDs useful for multiple purposes, there are complexities in their characterization. Various characterization techniques exist for characterizing CDs, ranging from basic methods to confirm the presence of CDs to advanced methods that require an understanding of their structure. This chapter will comprehensively discuss all techniques used to understand the structure of CDs, including UV-Vis spectroscopy, photoluminescence (PL), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), dynamic light scattering (DLS), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), nuclear magnetic resonance spectroscopy (NMR), zeta potential, X-ray diffraction (XRD), electron spin resonance spectroscopy (ESR), and thermogravimetric analysis (TGA). This collective data will assist researchers in selecting appropriate characterization methods and making informed choices for applications.