In this paper, the extension of numerical simulation techniques to the analysis of light-addressable potentiometric sensors (LAPS) is discussed in detail, To this purpose, proper physical models of both the ion-sensitive and the photo-sensitive transduction mechanisms have been incorporated into the framework of a general-purpose device simulator, A self-consistent, accurate picture of charge transport within the device under the combined action of electrolyte ion layers and of luminous stimulus is recovered, which in turn, allows for detailed analysis of the device behavior and for fine-tuning of fabrication process. Extensive comparison with actual LAPS measurement has been performed, validating the tool and illustrating its flexibility and application range.