Atomic partial charges are crucial parameters in molecular dynamics (MD) simulation, dictating the electrostatic contributions to intermolecular energies, and thereby the potential energy landscape. Traditionally, the assignment of partial charges has relied on surrogates of ab initio semiempirical quantum chemical methods such as AM1-BCC, and is expensive for large systems or large numbers of molecules. We propose a hybrid physical / graph neural network-based approximation to the widely popular AM1-BCC charge model that is orders of magnitude faster while maintaining accuracy comparable to differences in AM1-BCC implementations. Our hybrid approach couples a graph neural network to a streamlined charge equilibration approach in order to predict molecule-specific atomic electronegativity and hardness parameters, followed by analytical determination of optimal charge-equilibrated parameters that preserves total molecular charge. This hybrid approach scales linearly with the number of atoms, enabling, for the first time, the use of fully consistent charge models for small molecules and biopolymers for the construction of nextgeneration self-consistent biomolecular force fields. Implemented in the free and open source package espaloma_charge, this approach provides drop-in replacements for both AmberTools antechamber and the Open Force Field Toolkit charging workflows, in addition to stand-alone charge generation interfaces. Source code is available at https://github.com/choderalab/espaloma_charge. Molecular mechanics (MM) force fields abstract atoms as point charge-carrying particles, with their electrostatic energy ( ) calculated by some Coulomb's law [10](or some modified form), where is Coulomb constant (energy * distance 2 / charge 2 ) and the interatomic distance. In fixed-charge molecular mechanics force fields, the partial charges are treated as constant, static parameters, agnostic of instantaneous geometry. As such, partial charge assignment-the manner in which partial charges are assigned to each atom in a given system based on their chemical environmentsplays a crucial role in molecular dynamics (MD) simulation, determining the electrostatic energy ( ) at every step and shaping the energy landscape.