Gallium Nitride (GaN) based devices such as the High Electron Mobility Transistors (HEMTs) find wide applications in RF and Power domain due to its excellent intrinsic properties. Accordingly, such devices have also been explored for their radiation hardness which is inherent due to the strong bonding nature of the binary and ternary nitrides. Radiation-induced instabilities including the radiation-induced stress and changes to the material properties leading to the departure of expected results in practical applications. Due to the limited availability of the test structures and facilities required to analyze the reliability of said devices under ionizing radiations, the cost and time of production gets affected. In this regard, to cut down on the cost and time for production, device engineers require accurate and reliable tools that can accurately predict the robustness of their proposed device architectures in foreign environments. Silvaco’s Victory TCAD software is one such tool that can aid the device engineers in this aspect. In this work, we demonstrate the Total Ionizing Dose (TID) Effects on GaN HEMTs using the Radiation Effects Module (REM) available with Silvaco’s Victory TCAD suite.