Single-cell metabolomics has been developed as a revolutionary method for clarifying cellular heterogeneity in metabolic activity and biochemical pathways at the individual cell level. In contrast to bulk metabolomics, which averages signals from cell populations, single-cell approaches provide high-resolution insights into individual cell metabolic states, disease processes, and microenvironmental responses. Recent improvements in analytical platforms—specifically high-sensitivity mass spectrometry, microfluidic integration, and computational data deconvolution—have greatly enhanced the scope and accuracy of single-cell metabolomics analysis. This chapter offers a thorough examination of contemporary techniques, clinical applications, and translational prospects of single-cell metabolomics, while also confronting ongoing problems like sample throughput, data standardization, and integration with multiomics frameworks.