A drying kiln is a complex system where various mechanisms are involved in the process to reduce the wood moisture content. To represent adequately the full drying process inside the kiln, a numerical model has to account for moisture transport not only inside the wood, but outside the wood, and in the airflow, as well. In this research, two sub-models describing airflow and wood drying are integrated into one comprehensive model. A detailed summary of both the airflow and wood drying models is given, together with a description of the coupling procedure between them. An example is shown to indicate possible benefits of using the model for the improvement of the drying quality in a typical kiln. The performance of the model is validated by comparison of the computational results with experimental data for a small test kiln. The presented model may be utilized for the design of new kilns, as well as for the optimization of existing ones. Different drying conditions, various schedules, and lumber arrangements can be studied in depth without costly experiments.