Composition fluctuations are commonly observed in additive manufactured alloys, high entropy alloys, and alloys under irradiation. These fluctuations, which arise due to thermodynamic and/or kinetic factors, influence the yielding strength of alloys. In the classical literature, the theory of spinodal strengthening in alloys with coherent long-range composition fluctuations was developed by Cahn [1] and Kato [2]. We revisit Cahn’s theory to account for the concurrent solid solution strengthening in spinodally strengthened alloys by taking into consideration the effect of the solute friction along with the internal coherency stress. A new definition of the incremental critical resolved shear stress (CRSS) associated with spinodal hardening is introduced, with that of the homogeneous alloy being the reference. For the BCC FeCrAl ternary alloy, we show that the friction stress due to solute influences the incremental CRSS for spinodal strengthening, and that influence is strongly dependent on dislocation line direction and the location of the slip plane in the composition landscape. The CRSS will be presented for both primary ({110}〈111〉) and secondary ({112}〈111〉) slip systems. The effects of the amplitude and wavelength of the composition fluctuations are also discussed. A key result of the current investigation is the dependence of the incremental CRSS for spinodal hardening on the average composition of the alloy. A dislocation dynamics generalization of the new theory to the case of irregular and stochastic spinodal-like composition morphologies arising due to non-equilibrium kinetics in irradiated alloys will be presented. It will be shown that this work paves the way to incorporate the physical effects associated with composition inhomogeneity in dislocation dynamics simulations, making the method composition-aware. This work has been performed in collaboration with Riccardo Civiero, Khaled SharafEldin, Manikandan Muruganandam, Kieran Edmonds (Purdue University, USA), and Yash Pachaury (formerly with Purdue University, USA).