In this work, we investigate the impact of Gallium Nitride (GaN) based Single Gate Tunnel field effect transistors (SG TFET) and Gate All Around (GAA) TFET by using analytical models. The models are derived by solving the 2D-Poisson’s equation and Parabolic Approximation Technique. The analytical model includes the calculation of the surface potential, lateral electric field and vertical electric field. Finally the drain current is extracted by using Kane’s model. The device simulations are carried out using 2-D device simulator, Technology Computer Aided Design (TCAD). The model can be used to study the impact of GaN based SG TFET and GAA TFET in terms of higher ON current characteristics. The results expected by the model are compared with those obtained by 2-D simulation to verify the accuracy of the proposed analytical model.