The Septinsular Republic (Greek: Ἑπτάνησος Πολιτεία, romanized: Heptanēsos Politeia; Italian: Repubblica Settinsulare) was an oligarchic republic that existed from 1800 to 1807 under nominal Russian and Ottoman sovereignty in the Ionian Islands (Corfu, Paxoi, Lefkada, Cephalonia, Ithaca, Zakynthos, and Kythira).

The Republic was established after a joint Russo-Ottoman fleet captured the islands and ended a two-year rule by the French Republic. Although the islanders had hoped for complete independence, the new state was granted only autonomy, becoming tributary to the Ottoman Porte. Nevertheless, it was the first time Greeks had been granted self-government since the fall of the last remnants of the Byzantine Empire to the Ottomans in 1460. In 1807, the republic was ceded to Napoleon's French Empire, but the islands were not annexed by France, keeping their institutions of government. The British gradually took control of the islands, and following the Treaty of Paris, the islands were formally organised into the United States of the Ionian Islands under British protection.