  We discuss non-renormalization theorems applying to galileon field theories
and their generalizations. Galileon theories are similar in many respects to
other derivatively coupled effective field theories, including general
relativity and $P(X)$ theories. In particular, these other theories also enjoy
versions of non-renormalization theorems that protect certain operators against
corrections from self-loops. However, we argue that the galileons are
distinguished by the fact that they are not renormalized even by loops of other
heavy fields whose couplings respect the galileon symmetry.
