The Cascais and Oeiras Chamber Orchestra (OCCO), founded in 1999, is a formation supported by the Municipalities of Cascais and Oeiras and by the General Directorate of Arts.  

Considered one of the best training courses of its kind in Portugal, OCCO is currently a fundamental element of the cultural life of the Municipalities of Oeiras and Cascais. In addition to an intense season divided between symphonic concerts, chamber music recitals and animations, there are performances in almost all regions of Portugal and several performances abroad.

In 2008, OCCO created the first Official Music Conservatory in the Municipality of Cascais. As of 2014, it began holding International Meetings for young instrumentalists with the aim of increasing its presence at an international level.

OCCO has collaboration protocols with two of the most prominent national competitions: Young Musicians RDP Award and Estoril Interpretation Contest.

In its repertoire, OCCO gives particular emphasis to the dissemination of works by national composers and works by foreign composers in absolute premieres in Portugal.

OCCO performed in all national festivals. Internationally, its presentation during the General Assembly of the European Festivals, in Estoril, at the Festivals in Bulgaria, Spain, Italy and, recently, in Germany, in the famous Tonhalle Room in Düsseldorf, stands out.

Among the many soloists and conductors who worked with OCCO, we highlight Lídia Mordkovitch, Alberto Lysy, Paul Badura-Skoda, Sequeira Costa, Stoika Milanova, Darco Brlek, Pedro Leon, Márcio Carneiro, Plamena Mangova and conductors Ricardo Averbach (USA), Bernardo Adam Ferrero (Spain), Sandor Gyudi (Hungary), Stefan Fraas (Germany) and Jesus Medina (Mexico).

National artists worked with OCCO, including Manuel Ivo Cruz, Jorge Matta, Ana Bela Chaves, Aníbal Lima, Olga Prats, António Rosado, Miguel Henriques, Pedro Carneiro, Teresa Menezes, Ana Paula Russo, Luís Rodrigues, Sandra Medeiros Gonçalo Pescada, between others.

In 2012, the Municipality of Cascais awarded OCCO the Medal of Cultural Merit for its contribution to culture and art.

In the year of its 20th anniversary, OCCO was granted High Sponsorship by the Presidency of the Portuguese Republic. OCCO was created and is currently directed by Maestro Nikolay Lalov.

​