A function f: V( G ) → { - 1,1} defined on the vertices of a graph G is a signed total dominating finction (STDF) if the sumof its function values over any open neighborhood is at least one. An STDF f is minimal if there does not exist a STDF g: V ( G ) →{ - 1,1} , f ≠ g, for which g ( v ) ≤f( v ) for every v ∈ V( G ). The weight of a STDF is the sum of its function values over all vertices. The signed total domination number of G is the minimum weight of a STDF of G, while the upper signed domination number of G is the maximum weight of a minimal STDF of G. In this paper, we present sharp upper bounds on the upper signed total domination number of a nearly regular graph.