We develop parameters for the interlayer Kolmogorov–Crespi (KC) potential to study structural features of four transition-metal dichalcogenides (TMDs): MoS$_2$, WS$_2$, MoSe$_2$, and WSe$_2$. We also propose a mixing rule to extend the parameters to their heterostructures. Moiré superlattices of twisted bilayer TMDs have been recently shown to host shear solitons, topological point defects, and ultraflat bands close to the valence band edge. Performing structural relaxations at the density functional theory (DFT) level is a major bottleneck in the study of these systems. We show that the parametrized KC potential can be used to obtain atomic relaxations in good agreement with DFT relaxations. Furthermore, the moiré superlattices relaxed using DFT and the proposed force field yield very similar electronic band structures.