The great majority of Ecuadorians trace their origins to one or more of three geographical sources of human migrations: the pre-Hispanic indigenous populations who settled the region over 15,000 years ago, the Europeans (principally Spaniards) who arrived over five centuries ago, and ultimately the black sub-Saharan Africans whom they imported as slave labor during the same period. The mixing of two or more of these three groups established other mixed ethnic groups.

Mestizos, the multiracial group of mixed European and Amerindian ancestry, are by far the largest of all the ethnic groups and comprise around 71.9% of the current population. Whites are estimated at 6.1% and consist largely of those of unmixed or predominant European descent.

 Most white Ecuadorans are of colonial-era Spanish origin, also known as criollos (literally meaning "local-born Spaniards", as opposed to "Peninsulares", which were Spaniards born in the Iberian Peninsula in Spain. They also include descendants of immigrants from Italy, Germany, and France, as well as other countries. 

The third most numerous group are the indigenous Amerindians, who account for approximately 7% of the population. Afro-Ecuadoreans make up most of the balance of the percentage and include mulattos (mixed European and sub-Saharan African) and zambos (mixed indigenous and sub-Saharan African).

Most Ecuadorians speak Spanish, though many speak Amerindian languages such as Kichwa. Other Amerindian languages spoken in Ecuador include Awapit (spoken by the Awá), A'ingae (spoken by the Cofan), Shuar Chicham (spoken by the Shuar), Achuar-Shiwiar (spoken by the Achuar and the Shiwiar), Cha'palaachi (spoken by the Chachi), Tsa'fiki (spoken by the Tsáchila), Paicoca (spoken by the Siona and Secoya), and Wao Tededeo (spoken by the Waorani). Though most features of Ecuadorian Spanish are those universal to the Spanish-speaking world, there are several idiosyncrasies.