São Tomé Island is, at 854 km², the largest island of São Tomé and Príncipe and is home to 96% of the nation's population. It rises to 2,024 metres at Pico de São Tomé and includes the capital city, São Tomé, on the north east coast.

Villages on the island include Porto Alegre , São João dos Angolares, Ribeira Afonso , Santana , Trindade, Bom Successo , Guadalupe , Neves and Santa Catarina .

The higher slopes of the island are forested and form part of the Obo National Park , but agriculture is important near the north and east coasts. The chief exports are cocoa, coffee, copra, and palm products, while there is also a fishing industry.

Large reserves of oil are in the ocean between Nigeria and São Tomé. The discovery has been lamented by some as endangering the nation's political stability and natural environment. In response to these concerns the government of São Tomé and Príncipe has drawn up legislation in an attempt to ensure the efficient and equitable use of oil revenues over time.