Berry phase is a well-known feature of quantum mechanics. In this talk I will discuss the less-explored subject of Berry phase in quantum field theory. We will see that even simple quantum field theories can exhibit non-trivial Berry phases, and will discuss an explicit example in axion electrodynamics. We will also discuss a general relation between the Berry connection in conformal field theories with non-trivial conformal manifolds and the connections previously considered by several authors in conformal perturbation theory. The implementation of this relation in 2d N=(2,2) and 4d N=2 superconformal field theories leads to a useful re-derivation of the tt* equations.