The Péninsule Rallier du Baty, or Presqu'ile Rallier du Baty, is a peninsula of Grande Terre, the main island of the subantarctic Kerguelen archipelago in the southern Indian Ocean. It occupies the south-western corner of the island, and is about 35 km long, extending from north to south, and 25 km across at its widest. It is named for Raymond Rallier du Baty, a French sailor who charted the archipelago in the early 20th Century.