The Avalon Peninsula is a large peninsula (9,220 km²) that makes up the southeast portion of the island of Newfoundland.

The peninsula is home to 262,410 people, about 51% of Newfoundland's population, according to the Canada 2011 Census. The peninsula is the location of St. John's, the provincial capital and largest city. It is connected to the main section of the island by the 5 km (3 mi) wide Isthmus of Avalon. The peninsula protrudes into the rich fishing zones near the Grand Banks. Its four major bays—Trinity Bay, Conception Bay, St. Mary's Bay, and Placentia Bay—have long been the centre of Newfoundland's fishing industry.