The Jahn-Teller distortion, by its very nature, is often at the heart of the various electronic
properties displayed by perovskites and related materials. Despite the Jahn-Teller mode being
non-polar, we devise and demonstrate in the present letter an electric field control of Jahn-Teller
distortions in bulk perovskites. The electric field control is enabled through an anharmonic lattice
mode coupling between the Jahn-Teller distortion and a polar mode. We confirm this coupling
and quantify it through first-principles calculations. The coupling will always exist within the
P b21m space group, which is found to be the favoured ground state for various perovskites under
sufficient tensile epitaxial strain. Intriguingly, the calculations reveal that this mechanism is not
only restricted to Jahn-Teller active systems, promising a general route to tune or induce novel
electronic functionality in perovskites as a whole.