Given that the anisotropy in the thermal transport in the flagship thermoelectric SnSe plays an important role in its large high-temperature figure of merit, we also investigated the anisotropy in the κ latt (Table and Figs S10-S12, ESI † ). For the tetragonal I4/mcm and rhombohedral R3m spacegroups of STO and BTO, respectively, symmetry dictates that κ xx = κ yy ̸ = κ zz , whereas in the lower-symmetry orthorhombic Pnma spacegroup of CTO the κ xx ̸ = κ yy ̸ = κ zz . For STO and BTO, we predict κ xx = κ yy < κ zz , while for CTO we predict κ xx ≈ κ yy > κ zz . The anisotropy in CTO and BTO is relatively small, with a maximum variation of 4-5% in the directional components relative to the average, whereas STO shows a larger anisotropy of around 15%, comparable to the size of the predicted anisotropy in the electrical conductivity of CTO.