Monte Carlo (MC) simulations are known to be the most accurate method to model radiation transport and absorbed dose. Geant4 application for tomographic emission (GATE) is a Monte Carlo simulation platform built and is relatively new at modeling radiotherapy systems. A MC model of the Brainlab Novalis Classic 6 MV was developed using GATE which will investigate GATE’s capabilities in the application of a stereotactic radiosurgery (SRS) dedicated linear accelerator. Measured depth dose distributions and dose profiles using an ion chamber, diode detector, and radiochromic film are used as reference measurements for the model. The model shows agreement with the measured data with greater than 90% of points passing a 3%/1mm gamma comparison, with the exception of smaller field sizes in the penumbra region which still agree within 3%/3mm. This model demonstrates GATE ability to model linacs and can be used in the future for research and clinical comparisons.