In this work, we developed a reactive force field description for Mg/O systems for the ReaxFF framework. Magnesium-magnesium interactions were obtained using the KVIK optimization routine designed explicitly for metallic systems, while magnesium-oxygen interactions were trained using the SOPPI optimizer. As a result, the force field can reliably reproduce the bulk, surface, adsorption, and diffusion properties of both metallic Mg and the MgO salt.