Kvitsøy is an island municipality in Rogaland county, Norway. At only 6.29-square-kilometre (2.43 sq mi), it is the smallest municipality in Norway by area. Kvitsøy is located in the traditional district of Ryfylke. The administrative centre of the municipality is the village of Ydstebøhamn on the island of Kvitsøy. The municipality is an archipelago located at the entrance to the large Boknafjorden. It sits about 2 nautical miles (3.7 km; 2.3 mi) northwest of the mainland Stavanger peninsula. There are plans for the Rogfast tunnel to eventually connect Kvitsøy to the mainland road network.
The islands of Kvitsøy were established as a municipality on 1 January 1923 when they were separated from the municipality of Mosterøy on 1 January 1923. Initially, the municipality had 581 residents. The municipal boundaries have not changed since that time.
The Old Norse form of the name was Hvítingsøy(jar) which means "the white island(s)", probably because there is white quartz in the rocks on the islands. Originally, the spelling of the municipality was "Kvitingsø", but later it was shortened to "Kvitsøy".
Kvitsøy or Kvitsøya is the main island in Kvitsøy municipality in Rogaland county, Norway. The 2.3-square-kilometre (0.89 sq mi) island is one of 167 islands and skerries that make up the municipality. The island is home to most of the municipal residents, as well as the majority of the municipality's land area. The main population centre on the island is the village of Ydstebøhamn on the southern coast. The Kvitsøy Church and Kvitsøy Lighthouse are both located on the island.
The island is only accessible by boat. The village of Ydstebøhamn has a ferry quay which receives regular ferries from the town of Skudeneshavn on the island of Karmøy across the Boknafjorden to the north, and to the village of Mekjarvik in Randaberg municipality across the Kvitsøyfjorden on the mainland to the south. The planned Rogfast undersea tunnel will connect Kvitsøy to the mainland to the north and south as part of the government's goal of providing a ferry-free European route E39 highway along the west coast of Norway.