Dysprosium (Dy)-doped Lithium Strontium Borate (LSB) phosphors were synthesized via solid-state reaction for potential application in thermoluminescence dosimetry. A series of LSB samples with varying Dy concentrations were prepared and subjected to comprehensive structural, morphological, and thermoluminescent (TL) characterizations to determine the optimal dopant concentration. X-ray diffraction (XRD) confirmed the formation of highly crystalline monoclinic phases, with observable peak shifts indicating successful Dy incorporation. Fourier transform infrared spectroscopy (FTIR) analysis revealed changes in absorption bands upon Dy3+ doping, indicating modifications in the bonding environment and structural symmetry of the host lattice. Surface morphology and elemental distribution were examined using scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) and mapping. High-resolution transmission electron microscopy (HRTEM) confirmed interplanar spacing consistent with ICDD data. X-ray photoelectron spectroscopy (XPS) confirmed Dy incorporation and provided insights into electronic transitions. Following structural validation all samples were irradiated using a 6 MV X-ray photon beam from a linear accelerator (LINAC) over a dose range of 0.5–10 Gy. TL analysis revealed a prominent glow peak with superior dosimetric characteristics in the sample doped with 0.9 mol% Dy, exhibiting a TL intensity approximately 18 times higher than that of undoped LSB. Linearity, sensitivity, fading, reusability, and minimum detectable dose were systematically evaluated. Kinetic parameter analysis using Chen’s peak shape method yielded activation energy, frequency factor, and mean life values, corroborating the experimental results. This study provides a novel insight into rare earth doped borate systems, laying the groundwork for their development as efficient and reliable dosimetric phosphors.