Abstract An open source aquatic optics Monte Carlo (AOMC) model is described and evaluated. The open source nature of the AOMC software allows for a complete peer review process. The AOMC model simulates apparent optical properties commonly measured in aquatic systems. These include spectral or non-spectral radiance, upwelling and downwelling planar and scalar irradiances. The model output can be in a non-gridded or gridded format with the latter used to simulate a radiometric image. In gridded mode, the user may specify a bottom target whose reflecting characteristics are independent from the surrounding water bottom boundary. In both gridded and non-gridded mode, the model inputs consist of depth dependent concentrations of the various components comprising the simulated aquatic environment, their inherent optical properties, and environmental characteristics such as skylight distribution and optical properties of the aquatic bottom boundary. The model is evaluated by comparing its output to: (1) a test of the model’s closure, (2) an evaluation of a known relationship, (3) the comparison with results from other published numerical models, and (4) the simulation of a spectral “pivot-point”. The results of the evaluation indicate good agreement between the model and the anticipated outcome.