The assessment of three antiviral medications, namely Abacavir (ABA), Lamivudine (LAMI), and Zidovudine (ZIDO) in combined pharmaceutical dosage form was accomplished by the development and validation of a high-performance liquid chromatographic technique. Using the Box-Behnken Design and the Design Expert® software (Version 11.0), the Analytical Quality by Design (AQbD) RP-HPLC method was created for the simultaneous quantification of drugs. The ideal circumstances for the composition of the mobile phase Methanol, Acetonitrile and Potassium dihydrogen phosphate (pH 3.5) 65:20:15% v/v/v on Shimadzu C18 column on an HPLC system with UV detection at 280 nm was used and a flow rate of 1.0 mL/min. It was discovered that the retention times (min) for ABA, LAMI, and ZIDO were 4.12, 6.71, and 9.25, in that order. Both the asymmetry factor and the number of theoretical plates fall within the bound. The ICH guideline was followed in the validation of the suggested approach. It was discovered that the linearity was 10–60 µg/mL ZIDO, 5–30 µg/mL LAMI, and 10–60 µg/mL ABA. Three stages of the recovery study were 50%, 100%, and 150%. With intentional parameter adjustments, the method's % RSD of peak area was less than 2%, demonstrating its robustness. The medication mixture assay shows no signs of excipient interference.