  Chameleons are scalar fields that couple directly to ordinary matter with
gravitational strength, but which nevertheless evade the stringent constraints
on tests of gravity because of properties they acquire in the presence of high
ambient matter density. Chameleon theories were originally constructed in a
bottom-up, phenomenological fashion, with potentials and matter couplings
designed to hide the scalar from experiments. In this paper, we attempt to
embed the chameleon scenario within string compactifications, thus UV
completing the scenario. We look for stabilized potentials that can realize a
screening mechanism, and we find that the volume modulus rather generically
works as a chameleon, and in fact the supersymmetric potential used by Kachru,
Kallosh, Linde and Trivedi (KKLT) is an example of this type. We consider all
constraints from tests of gravity, allowing us to put experimental constraints
on the KKLT parameters.
