  The splashback radius is a physical scale in dark matter halos that is set by
the gravitational dynamics of recently accreted shells. We use analytical
models and N-body simulations to study the dependence of splashback on dark
energy and screened modified gravity theories. In modified gravity models, the
transition from screened to unscreened regions typically occurs in the cluster
outskirts, suggesting potentially observable signatures in the splashback
feature. We investigate the location of splashback in both chameleon and
Vainshtein screened models and find significant differences compared with
$\Lambda$CDM predictions. We also find an interesting interplay between
dynamical friction and modified gravity, providing a distinctive signature for
modified gravity models in the behavior of the splashback feature as a function
of galaxy luminosity.
