The first humans to reach Guyana belonged to the group of peoples that crossed into North America from Asia perhaps as much as 35,000 years ago. These first inhabitants were nomads who slowly spread south into Central America and South America. Although great civilizations later arose in the Americas, the structure of Amerindian society in the Guianas remained relatively simple. At the time of Christopher Columbus's voyages, Guyana's inhabitants were divided into two groups, the Arawak along the coast and the Carib in the interior. One of the legacies of the indigenous peoples was the word Guiana, often used to describe the region encompassing modern Guyana as well as Suriname (former Dutch Guiana) and French Guiana. The word, which means ""land of waters,"" is highly appropriate, considering the area's multitude of rivers and streams.

Historians speculate that the Arawak and Carib originated in the South American hinterland and migrated northward, first to the present-day Guianas and then to the Caribbean islands. The peaceful Arawak, mainly cultivators, hunters, and fishermen, migrated to the Caribbean islands before the Carib and settled throughout the region. The tranquility of Arawak society was disrupted by the arrival of the bellicose Carib from the South American interior. Carib warlike behavior and violent movement north made an impact still discussed today. By the end of the fifteenth century, the Carib had displaced the Arawak throughout the islands of the Lesser Antilles. The Carib settlement of the Lesser Antilles also affected Guyana's future development. The Spanish explorers and settlers who came after Columbus found that the Arawak proved easier to conquer than the Carib, who fought hard to maintain their freedom. This fierce resistance, along with a lack of gold in the Lesser Antilles, contributed to the Spanish emphasis on conquest and settlement of the Greater Antilles and the mainland. Only a weak Spanish effort was made at consolidating Spain's authority in the Lesser Antilles (with the arguable exception of Trinidad) and the Guianas.

Guyana's ethnic mix is the direct product of the colonial economy. Except for the Amerindians and a few Europeans, the country's ethnic groups are the descendants of groups brought in to work the early plantations. An economy based on sugar production required a large labor force. Attempts to enslave the Amerindian population failed, and the planters soon turned to African slaves. By 1830 there were 100,000 such slaves in British Guiana.

After the abolition of slavery became totally effective in 1838, the planters found a new source of cheap labor in the form of indentured workers, foreigners recruited to work for a specific number of years, usually five, with the possibility of reenlisting for an additional period and eventually being repatriated. Even before slavery was abolished, the importation of indentured workers began. They were recruited from Portugal, India, China, and the West Indies. Although the terms of indenture were nearly as harsh as slavery, the planters succeeded in bringing about 286,000 persons into the country by the early twentieth century. More than 80 percent of these indentured workers were East Indians; their arrival would profoundly affect Guyana's ethnic composition and the nature of Guyanese society in general.