The Reactive Transport Code MIN3P: Multicomponent reactive transport modeling in variably saturated porous media. MIN3P is a general purpose flow and reactive transport code for variably saturated media providing a high degree of flexibility with respect to the definition of the reaction network. Advective-diffusive transport in the water phase and diffusive transport in the gas phase are included. Equilibrium reactions considered are aqueous complexation, gas partitioning between phases, oxidation-reduction, ion exchange, and surface complexation. The reaction network is designed to handle kinetically controlled intra-aqueous and dissolution-precipitation reactions, and the dissolution of non-aqueous phase liquids (NAPLs). All reactions can be defined through a database, not requiring external code generation by the user.