Sao Tome and Principe officially the Democratic Republic of Sao Tome and Principe , is an island country in the Gulf of Guinea, off the western equatorial coast of Central Africa. It consists of two archipelagos around the two main islands of São Tomé and Príncipe, about 140 km (87 mi) apart and about 250 and 225 km (155 and 140 mi) off the northwestern coast of Gabon.

The islands were uninhabited until their discovery by Portuguese explorers in the 15th century. Gradually colonized and settled by the Portuguese throughout the 16th century, they collectively served as a vital commercial and trade center for the Atlantic slave trade. The rich volcanic soil and proximity to the Equator made São Tomé and Príncipe ideal for sugar cultivation, followed later by cash crops such as coffee and cocoa; the lucrative plantation economy was heavily dependent upon imported African slaves. Cycles of social unrest and economic instability throughout the 19th and 20th centuries culminated in peaceful independence in 1975. São Tomé and Príncipe has since remained one of Africa's most stable and democratic countries.

With a population of 201,800 (2018 official estimate), São Tomé and Príncipe is the second-smallest African sovereign state after Seychelles, as well as the smallest Portuguese-speaking country. Its people are predominantly of African and mestiço descent, with most practicing Catholic Christianity. The legacy of Portuguese rule is also visible in the country's culture, customs, and music, which fuse European and African influences. São Tomé and Príncipe is a founding member state of the Community of Portuguese Language Countries.