In this paper, we represent 16-component sedenions, the generalization of octonions, which is noncommutative space–time algebra. The sedenions is neither a composition algebra nor a division algebra because it has zero divisors. Here we have formulated the sedenionic unified potential equations, unified fields equations and unified current equations of dyons and gravito-dyons. We have developed the sedenionic unified theory of dyons and gravito-dyons in terms of two eight-potentials leading to the structural symmetry between generalized electromagnetic fields of dyons and generalized gravito-Heavisidian fields of gravito-dyons. Thus we have obtained the sedenionic form of generalized Dirac–Maxwell’s equations, unified work–energy theorem (Poynting theorem), generalized unified gravi-electromagnetic force and other quantum equations of dyons and gravito-dyons in simple, compact and consistent way incorporating the non-associativity and non-commutativity of sedenion variables.