Abstract: High-resolution mass spectrometry (HRMS) has become an indispensable analytical tool in pharmaceutical, biomedical, environmental, and food sciences. Its ability to provide accurate mass measurements, high resolving power, and structural information makes it superior to conventional low-resolution mass spectrometry (LRMS) for complex sample analysis. HRMS enables the identification of unknown compounds, metabolite profiling, impurity characterization, biomarker discovery, and quality control of pharmaceuticals. This review discusses the fundamental principles, instrumentation, ionization techniques, data acquisition modes, advantages, limitations, and applications of HRMS, with particular emphasis on its role in pharmaceutical analysis and bioanalytical research.