Cyclodextrin (CD)-based nanoparticles (CD-NPs) have gained attention for their potential in sensing applications, particularly in the detection of small molecules. CDs are cyclic oligosaccharides composed of glucose units linked by α-1,4 glycosidic bonds, which allow them to form inclusion complexes with various organic molecules, especially those that are hydrophobic or lipophilic. This property positions CDs as candidates for diverse applications, including drug delivery and biosensing. In electrochemical sensing, CD-based materials have demonstrated utility by providing selectivity and sensitivity in recognizing biomolecules. The mechanism of detection involves the encapsulation of analytes within the cyclodextrin cavities through host–guest interactions. These inclusion complexes enhance the sensitivity and selectivity of sensing processes across various platforms, such as electrochemical, potentiometric, and fluorescent sensors. The optical characteristics of cyclodextrin-based structures ranging from monomers to nanoassemblies have shown promise in identifying a range of physiologically relevant substances. The integration of CDs in sensor systems has been explored for detecting environmental pollutants and biomolecules like proteins and nucleic acids, contributing to the development of biosensors for disease detection and monitoring therapeutic responses. Overall, cyclodextrin-based nanoparticles offer a versatile platform for innovative detection systems across fields such as drug discovery, environmental monitoring, and chiral sensing. This chapter aims to explore the latest advancements in cyclodextrin-based nanoparticles, particularly in their application within pharmaceutical detection technologies.