<p>This study describes the development and validation of two UV-visible spectrophotometric methods for the simultaneous quantification of sitagliptin phosphate monohydrate and gliclazide in fixed-dose pharmaceutical formulations. The combination, which was recently approved by the Central Drugs Standard Control Organization (CDSCO) in 2023, is used in the management of type 2 diabetes owing to its complementary pharmacological mechanisms and favorable safety profile. Spectrophotometry was selected as a simple, cost-eff ective yet reliable alternative to chromatographic techniques for routine quality-control analysis. Two methods — simultaneous equations and first derivatives — were developed using HPLC-grade methanol as a solvent and analyzed with a Shimadzu UV- 1800 double-beam spectrophotometer. Method validation was conducted in accordance with International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use (ICH) Q2(R2) guidelines. The methods demonstrated excellent linearity across the concentration ranges of 8–56 μg/mL for sitagliptin and 4.8–33.4 μg/mL for gliclazide, with correlation coefficients exceeding 0.999. Accuracy studies yielded recovery within acceptable limits, and precision was confirmed by low relative standard deviations. The first-order derivative method utilized zero-crossing wavelengths of 213.2 nm (sitagliptin) and 243.6 nm (gliclazide), whereas the simultaneousequation method used λ_max values of 268.0 and 228.4 nm, respectively. Both methods showed high sensitivity (limit of detection, limit of quantitation), reproducibility, and robustness. Statistical comparison using one-way ANOVA revealed no significant diff erence (p &gt; 0.05) compared with previously reported methods, confirming analytical equivalence. These validated methods are suitable for routine quality assessment and regulatory compliance of combined formulations, with future applicability in biological matrices.</p>