An automorphism α of a group G is called a noetherian automorphism if for each ascending chain $$ X_1 < X_2 < \ldots < X_n < X_{n + 1} < \ldots $$ of subgroups of G there is a positive integer m such that \(X_n^{\alpha} = X_n \) for all n ≥ m. The structure of the group of all noetherian automorphisms of a group is investigated in this paper.