Thermal screening masses of the conserved vector current are calculated both in a weak-coupling approach and in lattice QCD. The inverse of a screening mass can be understood as the length scale over which an external electric field is screened in a QCD medium. The comparison of screening masses both in the zero and non-zero Matsubara frequency sectors shows good agreement of the perturbative and the lattice results. Moreover, at T ≈ 508MeV the lightest screening mass lies above the free result (2πT), in agreement with the O(g2) weak-coupling prediction.