Established in 2010, the English-speaking school offers the International Baccalaureate program throughout all year groups.

[2] The school campus is based on the premises of a 17th-century palace,[2][3] the Quinta de Nossa Senhora da Conceição in Barcarena, Oeiras.

[2] OIS has ambitious plans to become an tensor Eco-School and intends to promote Environmental Awareness and Social Responsibility with the provision of scholarships and community service.

[5][6] The school motto is Sapere Aude (Dare to Learn).

[2] Quinta de Nossa Senhora da Conceição, à Rua Antero de Quental, Barcarena, 2780-001 Oeiras, Portugal [8]