655 (DCLV) was a common year starting on Thursday of the Julian calendar, the 655th year of the Common Era (CE) and Anno Domini (AD) designations, the 655th year of the 1st millennium, the 55th year of the 7th century, and the 6th year of the 650s decade. As of the start of 655, the Gregorian calendar was 3 days ahead of the Julian calendar, which was the dominant calendar of the time.

• November 15 – Northumbrian king Oswiu defeats the pagan Mercian king Penda in the Battle of the Winwaed
• Empress Saimei ascends to the throne of Japan.
• Clovis II succeeded by Clotaire III.
• Peada succeeds his father Penda as king of Mercia
• A Byzantine fleet is defeated by the Arabs at Finike.