根据考古研究及遗传学分析，至少在24,500年前育空北部即有人类活动，而南安大略的人类活动可以追溯到公元前7,500年。旧克罗平地和蓝鱼洞穴遗迹是加拿大境内最古老的人类居住地。原住民社会的特点包括有永久居住点、农业耕种、复杂的社会等级和贸易网络。一部分原住民文明在欧洲殖民者抵达加拿大前已瓦解，如今只能通过考古发掘研究那些文明。
在第一批欧洲殖民者定居加拿大时，原住民的人口总数估计为20万至200万。加拿大皇家原住民健康委员会的数据显示，现时约有50万名原居民居住在加拿大。由于缺乏相应免疫系统，原住民被殖民者带来的流感、麻疹、天花等传染病感染，人口锐减40%至80%不等。现今居住在加拿大的原住民为第一民族、因纽特人和梅蒂人，其中梅蒂人是原住民与法裔加拿大人的混血后代。而与其他原住民相比，因纽特人与欧洲殖民者的交流较少。
Indigenous peoples in present-day Canada include the First Nations, Inuit, and Métis, the last being a mixed-blood people who originated in the mid-17th century when First Nations and Inuit people married European settlers. The term "Aboriginal" as a collective noun is a specific term of art used in some legal documents, including the Constitution Act 1982.
The first inhabitants of North America are generally hypothesized to have migrated from Siberia by way of the Bering land bridge and arrived at least 14,000 years ago. The Paleo-Indian archeological sites at Old Crow Flats and Bluefish Caves are two of the oldest sites of human habitation in Canada. The characteristics of Indigenous societies included permanent settlements, agriculture, complex societal hierarchies, and trading networks. Some of these cultures had collapsed by the time European explorers arrived in the late 15th and early 16th centuries and have only been discovered through archeological investigations.
The Indigenous population at the time of the first European settlements is estimated to have been between 200,000 and two million, with a figure of 500,000 accepted by Canada's Royal Commission on Aboriginal Peoples. As a consequence of European colonization, the Indigenous population declined by forty to eighty percent, and several First Nations, such as the Beothuk, disappeared. The decline is attributed to several causes, including the transfer of European diseases, such as influenza, measles, and smallpox to which they had no natural immunity, conflicts over the fur trade, conflicts with the colonial authorities and settlers, and the loss of Indigenous lands to settlers and the subsequent collapse of several nations' self-sufficiency.
Although not without conflict, European Canadians' early interactions with First Nations and Inuit populations were relatively peaceful. First Nations and Métis peoples played a critical part in the development of European colonies in Canada, particularly for their role in assisting European coureur des bois and voyageurs in the exploration of the continent during the North American fur trade. The Crown and Indigenous peoples began interactions during the European colonization period, though the Inuit, in general, had more limited interaction with European settlers. However, from the late 18th century, European Canadians encouraged Indigenous peoples to assimilate into their own culture. These attempts reached a climax in the late 19th and early 20th centuries with forced integration and relocations. A period of redress is underway, which started with the appointment of the Truth and Reconciliation Commission of Canada by the Government of Canada in 2008.