In this study, effects on mixed convection heat transfer of oscillation parameters on a vertical flat plate surface subjected to constant heat flux are experimentally and numerically investigated. The experimental setup includes a hanger–pulley system installed above a transparent enclosure contain a moving experimental model, flywheel-motor assembly generating the oscillating movement of the experimental model, power supply, and datalogger. The experimental model comprises two copper plates with attached thermocouples and Kapton heaters placed between the plates. In the study, heat flux applied to surface of the plates (q″), the Womersley number (Wo) and dimensionless oscillation amplitude (Ao) are varied. The effects of these parameters on the heat transfer performance are analyzed. This study is numerically solved using a control-volume based Computational Fluid Dynamics solver based on experimental data. The numerical results are compared with the experimental results and open literature. Instantaneous velocity and temperature profiles on the plate are obtained to explain the heat transfer mechanism. According to the numerical and experimental results, heat transfer performance is significantly affected by os cillation parameters and he at flux applied to the plate surface. The mixed convection heat t ransfer increases with the increase in oscillation parameters for all tested heat fluxes. The obtained results are presented as a function of dimensionless numbers.