In this work, we apply this approach to the group II titanate perovskites CaTiO 3 (CTO), SrTiO 3 (STO) and BaTiO 3 (BTO), in the orthorhombic Pnma, tetragonal I4/mcm and rhombohedral R3m phases, respectively, allowing us to investigate the impact of the A-site cation and the structure type on the thermoelectric performance. We find that STO has the best electrical transport properties, whereas the lower-symmetry structure of CTO lends itself to a low κ latt . On the other hand, BTO is predicted to have a relatively high κ latt and limited σ due to the impact of piezoelectric scattering leading to short electron lifetimes. We predict maximal ZT max ≈ 0.2 and 0.5 at mid and high temperatures of 600 and 1000 K and doping levels on the order of 10 21 cm -3 . Industrially viable ZT max > 1 are only obtained at temperatures above ∼1500 K. The low-temperature ZT is limited by the large κ latt , arising from the strong chemical bonding and resultant large phonon group velocities, and could be mitigated as a positive side effect of the chemical modifications required to optimise the electrical properties. Our findings provide valuable insight to ongoing efforts to optimise these systems, and demonstrates that this ab initio workflow can provide useful predictions for other candidate oxide systems to support ongoing efforts to obtain highperformance oxide TEs.