This narrative review aims to provide an objective view of the non-invasive neuromodulation (NINM) protocols available for treating spasticity, including repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS). On the basis of the relevant randomized controlled trials, we infer that NINM is more effective in reducing spasticity when combined with the conventional therapies than used as a stand-alone treatment. However, the magnitude of NINM aftereffects depends significantly on the applied hemisphere and the underlying pathology. Being in line with these arguments, low-frequency rTMS and cathodal-tDCS over the unaffected hemisphere are more effective in reducing spasticity than high-frequency rTMS and anodal-tDCS over the affected hemisphere in chronic post-stroke. However, most of the studies are heterogeneous in the stimulation setup, patient selection, follow-up duration, and the availability of the sham operation. Therefore, the available data on the usefulness of NINM in reducing spasticity need to be confirmed by further larger and multicentric randomized controlled trials to gather evidence on the efficiency of NINM regimens in reducing spasticity in various neurologic conditions.