Experimental results from a gas absorption membrane (GAM) system were simulated using a comprehensive mathematical model. Originally, the model was developed to simulate carbon dioxide (CO2) absorption into aqueous solutions of monoethanolamine (MEA) in a packed column. The current work has modified the original model and demonstrates that packed-column models can be altered for membrane-based absorption systems, providing that the gas-liquid contacting mechanism is considered. The experimental data was generated using three GAM modules connected in series that contained microporous hollow-fiber poly-(tetrafluoroethylene) (PTFE) membranes. Simulation results showed that the model predicted the performance of the GAM system with reasonable accuracy. The average absolute deviation (ADD) of the model was 1.9%. This work has demonstrated that packed-column models can be modified with relative ease to simulate the performance of GAM systems.