The Siege of Patras in 805 or 807 is undertaken by the local Slavic tribes of the Peloponnese, reportedly with aid from an Arab fleet.

The siege's failure, attributed to the miraculous intervention of the city's patron, Saint Andrew, marks the consolidation of Byzantine control over the Peloponnese peninsula.

It also marks the beginning of the ascendancy of the Metropolis of Patras in the peninsula's ecclesiastical affairs.