The Einstein relation linking charge carrier mobility and diffusion coefficient is a fundamental principle of charge transport. However, in disordered organic semiconductors, energetic disorder and carrier filling in localized states lead to a concentration-dependent diffusivity–mobility ratio described by the generalized Einstein relation (GER). Carrier–carrier interactions may further modify carrier occupation and transport behavior in these systems. However, their role in determining GER remains largely unexplored, especially in multicomponent systems. Here, using three-dimensional kinetic Monte Carlo simulations, we investigate the impact of Coulomb correlation on the GER in pure materials, binary and ternary systems. We show that Coulomb correlation systematically modifies the GER, with the magnitude of the modification regulated by the relative permittivity, host–guest energy offset, guest concentration, temperature, and energetic disorder. The underlying mechanism is a interplay between energy-selective filling and Coulomb-induced carrier redistribution. In host–guest systems, the pronounced peak structures arising from multi-step filling are progressively modified by Coulomb correlation. These results provide a comprehensive understanding of how Coulomb correlation governs the GER in disordered organic semiconductors and offer valuable insights for parameterizing diffusivity and mobility in drift–diffusion simulations of organic electronic devices.