  We develop a theory of group actions and coverings on Brauer graphs that
parallels the theory of group actions and coverings of algebras. In particular,
we show that any Brauer graph can be covered by a tower of coverings of Brauer
graphs such that the topmost covering has multiplicity function identically
one, no loops, and no multiple edges. Furthermore, we classify the coverings of
Brauer graph algebras that are again Brauer graph algebras.
