The MOOSE geochemistry module can solve models involving aqueous geochemistry, including aqueous equilibrium, kinetics, oxidation-reduction, sorption and surface complexation, dissolution-precipitation and gas buffering. One aspect that makes the geochemistry module different to other codes is the ease of coupling additional physics to the geochemical functionality. In particular, when used in conjuction with the MOOSE PorousFlow module, sophisticated reactive-transport simulations may be performed, including multi-phase and unsaturated fluid flows, high-precision equations of state for fluids, dynamic porosity and permeability distributions, and sophisticated numerical stabilization. Geomechanics may also be incorporated by using MOOSE's TensorMechanics module, to explore the interplay between geomechanical stresses and strains, and fluids, heat and reactions. Geochemical models are used to understand the chemistry of natural waters and other aqueous solutions and their interaction with minerals in many areas of practical interest, for example, geothermal wells and reservoirs, contaminant flow through aquifers, ore creation and mining techniques, petroleum and gas exploitation, and rock diagenesis. The models are frequently extremely complicated, with thousands of interacting chemical species, and often require computer software to find the chemical concentrations. Reactive transport simulations involve predicting the transport of chemical-species and temperature in a spatial domain (such as an aquifer) in addition to solving a chemical model at each point, at each time, in the domain. Such models are used to explore spatio-temporal dependence of concentration, precipitation, dissolution, sorption, etc, and often require significant computational resources. The complexity of simulations is greatly increased when deformation of the subsurface is also modelled: deformation may occur through flow processes (e.g., via thermal expansion) or chemical changes (e.g., via dissolution weakening the rock). The MOOSE geochemistry module enables users to solve such models. For convenience, the source code for the geochemistry module is bundled within the MOOSE framework. Hence, this archive contains the entire MOOSE library. Wilkins, Green, Harbour and Podgorney do not claim authorship of the non-Geochemistry parts of MOOSE. See the COPYRIGHT file for copyright information. MOOSE is licensed under LGPL 2.1.