A samba school is a dancing, marching, and drumming club. They practice and often perform in a huge square-compounds and are devoted to practicing and exhibiting samba, an Afro-Brazilian dance and drumming style. Although the word "school" is in the name, samba schools do not offer instruction in a formal setting. Samba schools have a strong community basis and are traditionally associated with a particular neighborhood. They are often seen to affirm the cultural validity of the Afro-Brazilian heritage in contrast to the mainstream education system, and have evolved often in contrast to authoritarian development. The phrase "escola de samba" is popularly held to derive from the schoolyard location of the first group's early rehearsals. In Rio de Janeiro especially, they are mostly associated with poor neighborhoods ("favelas"). Samba and the samba school can be deeply interwoven with the daily lives of the shanty-town dwellers. Throughout the year the samba schools have various happenings and events, most important of which are rehearsals for the main event which is the yearly carnival parade. Each of the main schools spend many months each year designing the theme, holding a competition for their song, building the floats and rehearsing. It is overseen by a carnavalesco or carnival director. From 2005, some fourteen of the top samba schools in Rio have used a specially designed warehouse complex, the size of ten football pitches, called Samba City to build and house the elaborate floats. Each school's parade may consist of about 3,000 performers or more, and the preparations, especially producing the many different costumes, provide work for thousands of the poorest in Brazilian society. The resulting competition is a major economic and media event, with tens of thousands in the live audience and screened live to millions across South America.

Carnival or Shrovetide is a festive season that occurs at the close of the Christian pre-Lenten period, consisting of Quinquagesima or Shrove Sunday, Shrove Monday, and Shrove Tuesday or Mardi Gras.