Active resistive shim coil assemblies may be used in magnetic resonance imaging (MRI) systems to reduce in-homogeneity of the magnetic field in the imaging volume. Disclosed embodiments may be used with continuous systems, gapped cylindrical systems, or vertically gapped systems. Disclosed embodiments may also be used with an open MRI system and can be used with an instrument placed in the gap of the MRI system. An exemplary embodiment of the active resistive shim coil assembly of the present disclosure includes active resistive shim coils each operable to be energized by separate currents through a plurality of power channels. In some embodiments, the disclosed active resistive shim coil assemblies allow for various degrees of freedom to shim out field in-homogeneity.