The prime goal of this article is to characterize spacetimes endowed with H-flat curvature tensor. It is demonstrated that a 4-dimensional H-flat perfect fluid spacetime is either a de-Sitter spacetime or locally isometric to Minkowski spacetime under certain energy condition. Moreover, it is established that a Ricci simple H-flat spacetime becomes a Robertson-Walker spacetime. In addition, we shown that a Ricci simple spacetime with harmonic H-curvature tensor is a generalized Robertson-Walker spacetime. Also, we explain several conclusions based on H-flat generalized Robertson-Walker spacetimes. Finally, we investigate H-flat spacetimes that satisfy the f(r,T)-gravity.