  We study the automorphisms of Jha-Johnson semifields obtained from an
invariant irreducible twisted polynomial $f\in K[t;\sigma]$, where
$K=\mathbb{F}_{q^n}$ is a finite field and $\sigma$ an automorphism of $K$ of
order $n$, with a particualr emphasis on inner automorphisms and the
automorphisms of Sandler and Hughes-Kleinfeld semifields. We include the
automorphisms of some Knuth semifields (which do not arise from skew polynomial
rings). Isomorphism between Jha-Johnson semifields are considered as well.
