Abstract: The present study aimed to formulate and evaluate Withania somnifera-loaded Solid Lipid Nanoparticles (SLNs) to enhance drug delivery and therapeutic efficacy. Four formulations (F1–F4) were prepared using varying concentrations of formulation components and evaluated for physicochemical properties, drug-excipient compatibility, particle size, zeta potential, entrapment efficiency, in vitro drug release, and stability. Preformulation studies confirmed the suitability of Withania somnifera for SLN development, with a melting point range of 116–120°C and λmax at 227 nm in phosphate buffer pH 7.4. FTIR studies indicated the absence of significant interactions between the drug and excipients, confirming their compatibility. SEM analysis demonstrated smooth surface morphology of the nanoparticles. Particle size analysis revealed nanosized particles, with formulation F3 exhibiting an optimum particle size of 177 nm and a zeta potential of -32 mV, indicating good stability. Entrapment efficiency ranged from 75.63% to 81.24%, with F3 showing the highest entrapment efficiency (81.24%). In vitro drug release studies demonstrated sustained release behavior, and the optimized formulation F3 exhibited a maximum cumulative drug release of 95.74% over 8 hours. Stability studies conducted under various storage conditions for three months showed no significant changes in the formulation characteristics, confirming its stability. Based on the overall findings, formulation F3 was identified as the optimized SLN formulation with desirable physicochemical properties, high entrapment efficiency, sustained drug release, and good stability. Therefore, Withania somnifera-loaded SLNs may serve as a promising nanocarrier system for improving drug delivery and therapeutic outcomes.