Introduction: Orthoses have been reported to improve function and symptom reduction in knee Osteoarthritis (OA) of the medial compartment. Biomechanical changes introduced instantly in the gait with the use of orthoses can be evaluated to understand their effectiveness. Aim: To determine and compare the immediate effect of valgus knee brace and Lateral Wedge Insole (LWI) on gait parameters in medial compartment OA knee patients. Materials and Methods: This was a cross-sectional study conducted in the Department of Physical Medicine and Rehabilitation at a tertiary centre from August 2018 to July 2019. A 56 patients of knee OA (Kellgren-Lawrence system grades 2 or 3) were assessed by instrumented gait analysis before and just after orthotic fitment. Gait parameters related to External Knee Adduction Moment (EKAM) (e.g., maximum Ground Reaction Force (mGRF), vertical Ground Reaction Forces (vGRF), Varus Angle (VA) were assessed via motion capture during walking, in all four conditions: barefoot (B), LWI, valgus Knee brace (KB), Combined (C) i.e., (LW+KB). Statistical analysis was done using International Business Machines (IBM) Statistical Package for Social Sciences (SPSS) version 24.0. To find the significant difference in given parameters, repeated measure Analysis of Variance (ANOVA) was applied taking p-value <0.05. Results: A total of 56 patients (13 men, 43 women) mean age of 58.04±5.8 years and a mean Body Mass Index (BMI) of 27.4±3.5 kg/m2 were analysed. A 35 patients had OA grade 2 and 21 were classified as grade 3. No significant difference in mean vGRF and VA values was found among LW, KB and C (p=0.118) and (p=0.894) throughout the stance phase. The significant difference was in mean mGRF values during initial stance phase (0-20% of gait cycle) (p=0.036). Conclusion: The orthoses may not swiftly provide beneficial biomechanical changes in gait parameters of medial OA knee patients.