  Recent searches for parity breaking in the galaxy four-point correlation
function, as well as the prospects for greatly improved sensitivity to parity
breaking in forthcoming surveys, motivate the search for physical mechanisms
that could produce such a signal. Here we show that a parity-violating galaxy
four-point correlation function may be induced by lensing by a chiral
gravitational-wave background. We estimate the amplitude of a signal that would
be detectable with a current galaxy survey, taking into account constraints to
the primordial gravitational-wave-background amplitude. We find that this
mechanism is unlikely to produce a signal large enough to be seen with a galaxy
survey but note that it may come within reach with future 21cm observations.
