The Aupouri Peninsula is a tombolo at the northern tip of the North Island of New Zealand. It projects between the Tasman Sea to the west and the Pacific Ocean to the east.

It is a peninsula on a peninsula, being part of the massive North Auckland Peninsula which makes up nearly one twelfth of New Zealand's land area. Close to the northern town of Kaitaia, the North Auckland Peninsula suddenly narrows from a width of 60 kilometres to a mere 10 kilometres, a width which it maintains approximately for the last 100 kilometres of its thrust to the north. This is the Aupouri Peninsula.

At the base of the Aupouri to the east is the natural inlet of the Rangaunu Harbour. Beyond this lies a further short peninsula and the broad sweep of Doubtless Bay. The east coast of the Aupouri Peninsula is dominated by Rangaunu Bay in the south and Great Exhibition Bay in the north. Towards its northern tip is the natural inlet of Parengarenga Harbour, beyond which lies North Cape.

The Aupouri Peninsula's best known feature lies on the other coast. Almost the entire length of the west coast is accounted for by the erroneously named 80 kilometre stretch of Ninety Mile Beach.

At its northern end, the peninsula widens to 30 kilometres. Here are located the several capes which vie for the honour of the northernmost point on New Zealand's main islands: Cape Maria van Diemen, North Cape, Cape Reinga and the Surville Cliffs. The latter of these claims the title by a margin of only a few hundred metres. The Surville Cliffs lie at a latitude of 34° 23' 47" South. Only a handful of islands in the Three Kings and Kermadec chains lie further north in New Zealand.

The Aupouri Peninsula is sparsely habited, with no settlements with a population of over 100. For this reason, the area's roading is largely unsealed, and Ninety Mile Beach is often used as an unofficial highway. The nearest town to the capes at the tip of the peninsula is Kaitaia, 100 kilometres to the south.

It is named after Te Aupouri, one of the Maori tribes that inhabits it.