Classical shell-model- as well as embedded-cluster-type calculations are employed in order to supply theoretical arguments in favour of hole bipolarons in BaTiO3. In particular the embedded cluster modelling studies, which explicitly include the local electronic defect structure, suggest the importance of lattice relaxation and electron correlation terms in order to stabilize diamagnetic O22−molecules (bipolarons) in the material. Our simulations show that hole bipolarons are predominantly bound at Ti-site acceptor defects.