  We study Galois actions on $2+1$D topological quantum field theories (TQFTs),
characterizing their interplay with theory factorization, gauging, the
structure of gapped boundaries and dualities, 0-form symmetries, 1-form
symmetries, and 2-groups. In order to gain a better physical understanding of
Galois actions, we prove sufficient conditions for the preservation of
unitarity. We then map out the Galois orbits of various classes of unitary
TQFTs. The simplest such orbits are trivial (e.g., as in various theories of
physical interest like the Toric Code, Double Semion, and 3-Fermion Model), and
we refer to such theories as unitary "Galois fixed point TQFTs." Starting from
these fixed point theories, we study conditions for preservation of Galois
invariance under gauging 0-form and 1-form symmetries (as well as under more
general anyon condensation). Assuming a conjecture in the literature, we prove
that all unitary Galois fixed point TQFTs can be engineered by gauging 0-form
symmetries of theories built from Deligne products of certain abelian TQFTs.
