  We determine the general coupling of a system of scalars and antisymmetric
tensors, with at most two derivatives and undeformed gauge transformations, for
both rigid and local N=2 supersymmetry in four-dimensional spacetime. Our
results cover interactions of hyper, tensor and double-tensor multiplets and
apply among others to Calabi-Yau threefold compactifications of Type II
supergravities. As an example, we give the complete Lagrangian and
supersymmetry transformation rules of the double-tensor multiplet dual to the
universal hypermultiplet.
