  We present self-dual N=2 supergravity in superspace for Euclidean seven
dimensions with the reduced holonomy G_2 \subset SO(7), including all
higher-order terms. As its foundation, we first establish N=2 supergravity
without self-duality in Euclidean seven dimensions. We next show how the
generalized self-duality in terms of octonion structure constants can be
consistently imposed on the superspace constraints. We found two self-dual N=2
supergravity theories possible in 7D, depending on the representations of the
two spinor charges of N=2. The first formulation has both of the two spinor
charges in the {\bf 7} of G_2 with 24 + 24 on-shell degrees of freedom. The
second formulation has both charges in the {\bf 1} of G_2 with 16 + 16 on-shell
degrees of freedom.
