Gargalianoi () is a town and a former municipality in Messenia, Peloponnese, Greece. Since the 2011 local government reform it is part of the municipality Trifylia, of which it is a municipal unit. The municipal unit has an area of 122.680 km<sup>2</sup>. It is situated from the Ionian Sea coast, north of Pylos, south of Kyparissia and west of Kalamata. The Greek National Road 9 (Patras - Pyrgos - Pylos) passes through the town.
The municipal unit Gargalianoi is subdivided into the following communities: