  We endow the diffeomorphism group of a paracompact (reduced) orbifold with
the structure of an infinite dimensional Lie group modelled on the space of
compactly supported sections of the tangent orbibundle. For a second countable
orbifold, we prove that this Lie group is C^0-regular and thus regular in the
sense of Milnor. Furthermore an explicit characterization of the Lie algebra
associated to the diffeomorphism group of an orbifold is given.
