Bribie Island is the smallest and most northerly of three major sand islands forming the coastline sheltering the northern part of Moreton Bay, Queensland, Australia. The others are Moreton Island and North Stradbroke Island. Bribie Island is 34 kilometres (21 miles) long, and 8 kilometres (5.0 miles) at its widest. Archibald Meston believed that the name of the island came from a corruption of a mainland word for it, Boorabee meaning koala. However, the correct Joondaburri name for the island is Yarun.

Bribie Island hugs the coastline and tapers to a long spit at its most northern point near Caloundra, and is separated from the mainland by Pumicestone Passage. The ocean side of the island is somewhat sheltered from prevailing winds by Moreton Island and associated sand banks and has only a small surf break. The lee side is calm, with white sandy beaches in the south.

Most of the island is uninhabited national park (55.8 square kilometres or 21.5 square miles) and forestry plantations. The southern end of the island has been intensively urbanised as part of the City of Moreton Bay, the main suburbs being Bongaree, Woorim, Bellara and Banksia Beach. A bridge from Sandstone Point on the mainland to Bellara and Bongaree was completed in 1963.

Buckley's Hole, at the southern tip of the island, is an important bird habitat and refuge.

On 2 January 2022, the ocean broke through the narrow spit of the island 2 km from the northern tip (due to Cyclone Seth culminating with a king tide). This event created a new passage 200 metres wide. With the ocean waves now able to break onto the mainland at Golden Beach, there is significant concern for the effect this will have for residents and businesses there.

The island is composed of the same coastal sand plains found on the mainland. The sand has been blown in to two large, low-lying dunes, extending towards the north-west.

Crossing to southern part of the island from the mainland via the bridge, the first suburb to be encountered is Bellara. The other four suburbs in the southern half of the island are Woorim (about 7 kilometres (4.3 mi) away on the island's 'surf side'), Bongaree at the southern end of the island, on the 'calm side' or 'passage side' and Banksia Beach and White Patch at the northern end of the populated area, also on the 'passage side'. Two other localities, Welsby and Bribie Island North, make up the undeveloped northern part of the island.

Bribie Island North is part of the Sunshine Coast Region while all of the other suburbs on the island are part of the City of Moreton Bay.